From Digital to Material. Rethinking Cork in Architecture through CADCAM Technologies

UNIVERSIDADE TÉCNICA DE LISBOA INSTITUTO SUPERIOR TÉCNICO

FROM DIGITAL TO MATERIAL: RETHINKING CORK IN ARCHITECTURE THROUGH THE USE OF CAD/CAM TECHNOLOGIES

Author: José Pedro Ovelheiro Marques de Sousa Licenciatura in Architecture, FAUP, 1999 Master in Genetic Architectures, ESARQ‐UIC, 2002

Dissertation submitted in Partial Fulfillment of the Requirement for the Degree of Doctor of Philosophy in Architecture

PROVISORY DOCUMENT

October, 2009

Jose Pedro Sousa PhD Dissertation in Architecture, IST-UTL

Abstract

Abstract

Title: From Digital To Material: Rethinking Cork In Architecture Through The Use Of CAD/CAM Technologies Name:

José Pedro Sousa

PhD:

Architecture

Professor Doutor José Pinto Duarte

Supervisor:

Co-supervisor:

Professor Doutor Rui Baptista

Today, the use of CAD/CAM technologies has expanded the architect’s world of design and construction possibilities. A look into contemporary built works around the globe shows an increasing interest in exploring geometric freedom and customization possibilities. After craft and serial standardization paradigms, the building materials industry is facing new production challenges to match current architectural interests.

Considering its social and economic importance for Portugal and seeking opportunities for innovation, this thesis focus its attention on cork and, more specifically, on pure cork agglomerate. Unlike other traditional materials, this industry is still rooted in mechanical and standard modes of production. Despite its great ecological value and unique properties, this condition has strongly limited its potential for becoming an interesting material for architecture.

Aiming to rethink the application of pure cork agglomerate in architecture through the use of CAD/CAM technologies, this thesis proposes a strategy for integrating such technologies at the end of the production chain. By developing a set of CNC subtractive fabrication experiments on alternative 2D shape, surface texture and 3D form possibilities intended to create new pure cork agglomerate products, this thesis demonstrates the viability and the potential of implementing such technologies in practice. It also outlines further research possibilities for integrating CAD/CAM technologies in other phases of the production chain to increase efficiency, flexibility, and the potential for innovation.

Keywords:

Contemporary architecture; CAD/CAM technologies; mass customization; geometric freedom; cork; pure cork agglomerate.

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Resumo

iii

Resumo

Título: Do Digital ao Material: Repensando a Cortiça em Arquitectura através das Tecnologias de CAD/CAM Nome:

Doutoramento: Orientador:

Co-orientador:

José Pedro Sousa Arquitectura Professor Doutor José Pinto Duarte Professor Doutor Rui Baptista

Hoje em dia, o uso de tecnologias de CAD/CAM tem expandido o universo de possibilidades de projecto e construção em arquitectura. Uma leitura da arquitectura contemporânea à escala global revela um interesse crescente na exploração de uma grande liberdade geométrica e de possibilidades de personalização. Depois dos paradigmas da produção artesanal e da produção em série, a indústria de materiais de construção enfrenta novos desafios de produção para poder corresponder aos actuais interesse em arquitectura.

Considerando a sua importância para a economia Portuguesa e procurando oportunidades de inovação, a presente tese dedica a sua atenção à cortiça e, mais especificamente, ao aglomerado de cortiça puro. Ao contrário de outros materiais tradicionais, esta indústria encontra‐se ainda ligada a modos de produção mecânicos baseados na estandardização. Apesar do seu grande valor ecológico e propriedades físicas únicas, esta condição tem limitado o seu potencial de afirmação como material interessante para a arquitectura.

Ambicionando repensar a aplicação do aglomerado de cortiça puro em arquitectura através do uso de tecnologias de CAD/CAM, esta tese propõe uma estratégia de integração destas tecnologias no final da respectiva cadeia de produção. Através da realização de um conjunto de experiências de fabrico subtractivo CNC, incidindo sobre a produção de formas alternativas, nomeadamente, formas 2D, superfícies texturadas e formas 3D, com o intuito de criar novos produtos nesse material, esta tese demonstra a viabilidade e potencial da implementação dessas tecnologias na prática. No final, identifica ainda possibilidades de investigação futura sobre a integração das tecnologias de CAD/CAM noutras fases da cadeia de produção, com o objectivo de aumentar a eficiência, a flexibilidade e o potencial de inovação.

Palavras-Chave:

Arquitectura Contemporânea; CAD/CAM; Personalização em Série; Liberdade Geométrica; Cortiça; Aglomerado de Cortiça Puro.

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Jose Pedro Sousa PhD Dissertation in Architecture, IST-UTL

Acknowledgments

Acknowledgments

I would like to express my deep and sincere gratitude to my supervisor, Prof. José Pinto Duarte. I owe him my interest in doing PhD studies in Portugal, and finishing this dissertation would not have been possible without his invaluable support, encouragement, guidance and friendship.

I am profoundly thankful to my co‐advisor, Prof. Rui Baptista, for the interesting interdisciplinary discussions, insightful comments and continuous support in many ways, and also to my thesis committee, Prof. Branko Kolarevic and Prof. Amaral Fortes, whose ideas and seminal works remarkably influenced this thesis.

My deepest thanks go to Marta Malé‐Alemany, for her partnership in ReD’s intense and inspiring adventure, to Luis Gil, from INETI, for sharing his knowledge on cork and reviewed part of the thesis, and to Carlos Manuel, from AMORIM Isolamentos, who kindly accepted with enthusiasm to support this research. With his precious help, I could contact with the reality of cork industry and get the necessary materials for developing the practical experiments of this thesis. At AMORIM I want to also thank Lopes Infante and Nuno Faria.

This thesis is also indebted to the Fundação para a Ciência e a Tecnologia for its financial support, and to the IST‐UTL, IAAC, LASINDUSTRIA, VETOR3 and FEYODESIGN for providing the fabrication resources for carrying out the practical experiments of this work. I would like also to thank Fernando Oliveria, from Maiadouro, for his help with the dissertation printing.

I would like to express my gratitude to Prof. Emília Rosa, Prof. Miguel Matos Neves and Prof. Pedro Rosa (IST‐UTL), Prof. Larry Sass and Prof. Lorna Gibson (MIT), Prof. Martin Bechthold (Harvard) Prof. Detlef Mertins (U.Penn), Andres Chaszar, Cristina Veríssimo and Grace Sheldrick, for interesting discussions, reviews and support in many ways.

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Jose Pedro Sousa PhD Dissertation in Architecture, IST-UTL

Acknowledgments

At this special moment, I would like to remember Prof. Fernando Lisboa, with whom I discovered my interests in architecture ten years ago, and whose friendship I miss.

During this work I was tremendously fortunate to count with the precious encouragement, love and support of my friends. Among them, my special thanks to Artur Fontinha, Carolina Duarte and Diamantino Pinho, but also to Elisabete Anastácio, Inês d’Orey, Isabel Beleza, Joana Cameira, João Albuquerque, Luis de Sousa, Pilar Luz, Tao Zhu and my fellow Zé Luis Tavares. For different reasons and in different moments, all of them were and/or are becoming essential in my work and life.

And last but not least, I wish to thank my family and, in particular, to my sister Ana and brother Luis, for being very important in my life.

For their infinite patience, support and love, I dedicate this thesis to my parents Isalina and José Serafim.

Jose Pedro Sousa PhD Dissertation in Architecture, IST-UTL

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Table of Contents

Table of Contents

Chapter 1

Introduction

1.1

Motivations | 01

1.2

Scope | 05

1.3

Research Problem | 06

1.4

Methodology | 09

1.5

Contributions | 12

1.6

Organization | 13

01

Chapter 2

Architecture and Digital Technologies

2.1

Introduction | 17

2.2

The Analogical Condition | 18

2.3

The Digital Condition | 27 2.3.1

Phase 1: Productivity

2.3.2

Phase 2: Visualization

2.3.3

Phase 3: Conception

2.3.4

Phase 4: Construction

2.3.5

The Rise of Computer Networks

2.4

The Digital Impact on Materiality | 58

2.5

Conclusion | 63

2.6

References | 65

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Jose Pedro Sousa PhD Dissertation in Architecture, IST-UTL

Chapter 3

Table of Contents

Review of Relevant Digital Technologies

3.1

Introduction | 73

3.2

Design Technologies | 76

3.3

3.2.1

Computer­Aided Design ­ CAD

3.2.2

Computer­Aided Engineering ­ CAE

3.2.3

Computer­Aided Manufacturing ­ CAM

73

Manufacturing Technologies | 111 3.3.1

Additive Fabrication

3.3.2

Subtractive Fabrication

3.3.3

Formative Fabrication

3.3.4

Robotic Assembly

3.3.5

Additive Construction

3.4

Conclusion | 143

3.5

References | 146

Chapter 4

Cork and Architecture

4.1

Introduction | 151

4.2

Reviewing Cork | 152

4.3

4.2.1

The Origins

4.2.2

Properties

4.2.3

Products and Applications

4.2.4

Significance

151

The Pure Cork Agglomerate | 177 4.3.1

Research Interests

4.3.2

Production Process

4.3.3

Properties

4.3.4

Products and Applications

4.3.5

Innovative References

4.4

Conclusion | 215

4.5

References | 219

Chapter 5

CAD/CAM Experiments with Pure Cork Agglomerate

5.1

Introduction | 223

5.2

Testing Conditions | 228 5.2.1

CAD/CAM Software

5.2.2

CNC Fabrication Technologies

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Jose Pedro Sousa PhD Dissertation in Architecture, IST-UTL

5.3

Experiment: Preliminary Test | 234 E.0.1

5.4

5.4

5.5

5.6

Milling

Experiments: 2D Shape | 237 E.1.1

Contour Geometry

E.1.2

Contour tolerance

E.1.3

Design Test – “Clover Panel”

Experiments: Surface Texture | 257 E.2.1

Step­Over Parameter

E.2.2

Step­Down Parameter

E.2.3

Speed Parameters

E.2.4

Tool Geometry

E.2.5

Design Test – “Waving Panel”

Experiments: 3D Form | 280 E.3.1

Design Test I – “CorkStruct”

E.3.2

Design Test II – “Free Form Panel”

Experiments: Other | 294 E.4.1

5.7

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Table of Contents

Design Test – “Cork Stoppers Panel”

Conclusion | 299

Chapter 6

Conclusion

6.1

The Digital Condition for Material Innovation | 302

6.2

Rethinking Cork in Architecture | 303

6.3

Future Research Directions | 310

6.4

Ending Note | 312

301

Source of Illustrations

313

Appendix

319

A

Summary of CAD/CAD Experiments with Cork | 319

B

Computational Design Studies | 325

C

CAD/CAM Studies | 333

D

Published Research on Architecture and Digital Technologies | 341

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Jose Pedro Sousa PhD Dissertation, IST-UTL

List of Acronyms

List of Acronyms

Technology

CAD

Computer Aided Design

CAE

Computer Aided Engineering

CAM

Computer Aided Manufacturing

CNC

Computer Numerical Control

FDM

Fused Deposition Modeling

RM

Rapid Manufacturing

RP

Rapid Prototyping

SLA

Stereolitography

SLS

Selective Laser Sintering

3DP

Three Dimensional Printing

Entities and Schools

Columbia U.

Columbia University, New York, NY, USA

ESAP

Escola Superior Artística do Porto, POrtugal

ESARQ‐UIC

Escola Superior d’Arquitectura, Universitat Internacional de Catalunya, Barcelona, Spain

FAUP

Faculdade de Arquitectura da Universidade do Porto, Porto, Portugal

Harvard GSD

Harvard University, Graduate School of Design, Cambridge, MA, USA

IAAC

Institute for Advanced Architecture of Catalonia, Barcelona, Spain

INETI

Instituto Nacional de Engenharia, Tecnologia e Inovação, Lisbon, Portugal

IST‐UTL

Instituto Superior Técnico, Universidade Técnica de Lisboa, Lisbon, Portugal

MIT

Massachussets Institute of Technology, Cambridge, MA, USA

ReD

ReD, Research + Design, Porto, Portugal, Barcelona, Spain

SCI‐Arc

Southern California Institute of Architecture, Los Angeles, CA, USA.

U. Minho

Universidade do Minho, Guimarães, Portugal

U.Penn

University of Pennsylvanya, Philadelphia, PA, USA

Yale U.

Yale University

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Chapter 1 Introduction

Chapter 1

Introduction

1.1

MOTIVATIONS

The origins of this dissertation can be found at two levels: a personal and a disciplinary one. On the one hand, from the personal point of view, early works and interests have made this thesis and its scope a natural step in my trajectory. On the other hand, disciplinary reasons have led to the framing and definition of the specific research problem. Following, I elaborate further on these motivations, which were materialized in the present thesis titled: From Digital to Material: Rethinking Cork in Architecture through the use of CAD/CAM technologies.

Personal motivations The beginning of a personal interest in the realm of digital technologies and architecture can be recognized when I wrote my graduation thesis at FAUP in 1999, called “The Architecture on Screen”. Framed in cultural, technological and disciplinary contexts, this work investigated the different modes and purposes of digital representations in architecture, focusing on contemporary examples to propose a classification. The main scope of this research was thus inscribed in the narrow field of Computer Aided Design (CAD) technologies, which was at that time mainly focused on drafting, modeling, visualization, and description of virtual environments.

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Chapter 1 Introduction

Then, the enrolment and completion of a Master in Genetic Architectures at ESARQ‐UIC in 2002 gave me the opportunity to contact with the use of Computer Aided Manufacturing (CAM) technologies. During that time in Barcelona, it was possible to study and experimenting with advanced digital tools, and contacting with a group of relevant architects working in this field, who visited the school. Following this experience, my personal interest in a digital approach to architecture shifted to the design conception and materialization aspects, converging to the study of parametric CAD/CAM processes. This shift was manifested in design research projects, like “BCN Strips – Boardwalk Re‐Design” and “Flex_H, Flexible Housing Research Project”. [Fig. 1.01]

Figure 1.01

Since then, my interest in CAD/CAM followed a double path:

Master projects on digital



in academic, by teaching undergraduate and master courses, and workshops; [Fig. 1.02]



in practice, by co‐orienting a studio called ReD | Research+Design1.

[Fig. 1.03]

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ReD | Research + Design is a design practice co‐founded with Marta Malé‐Alemany which was

dedicated to explore in real architectural projects, the conceptual and material opportunities emerging from the use of CAD/CAM technologies.

technologies: BCN Strips (top) and Flex_H (bottom).

(J.P.Sousa)

Jose Pedro Sousa PhD Dissertation, IST-UTL

Chapter 1 Introduction

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Figure 1.02 Student works developed in the courses and workshops taught by the author.

Figure 1.03 Works by ReD, revealing a deep interest in using CAD/CAM technologies in the production of architectural projects, exploring innovative applications for diverse materials. Projects from left to right: XURRET system, MORSlide, Dragorama and MCity Exhibition Design.

Although dealing with different worlds of constraints, both activities were dedicated to the investigation and practical testing of the application of advanced digital technologies to the design and manufacturing of architectural projects.

In this context, the enrollment in a Ph.D. program in 2003 became, naturally, understood as a desirable evolution for this research trajectory, as it would create opportunities for advanced investigation. Thinking in doing such research in Portugal, where these subjects were not so discussed and implemented yet, was a motivating challenge. While the IST at the Technical University of Lisbon appeared as the most obvious school to develop this kind of work, the possibility of getting some experience in relevant foreign

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Chapter 1 Introduction

institutions remained as an important goal, to acquire other skills and knowledge and complement the work at IST‐UTL. This glocal research condition was thus more than a personal desire but, above all, it was a necessity for developing research in the digital field.

Disciplinary motivations Aligned with the personal interests described before, the relation between digital technologies and architecture has affirmed itself as a major research field in the last fifteen years, due to its growing influence on contemporary culture and its ubiquity in the practice of the discipline. Subjacent to this trend, there was the idea, or the belief, that digital technologies have opened new design and material opportunities that could be perceived in contemporary architectural practices and built works. Therefore, investigating the CAD/CAM technologies that were supporting such work became the general research topic for this thesis.

In addition, the material link of such technologies required the integration of a practical dimension in the research. Indeed, the relevance of CAD/CAM technologies lay in going beyond the boundaries of design ideas virtually represented in the screens, to reach the world of materiality where they are ultimately tested. With such an understanding, this work was oriented to establish a close collaboration with the industry and, more specifically, with a company from the building construction materials’ area. By promoting the contact between the production of knowledge in the academia and the exterior reality of the industrial world, this decision represented an opportunity for addressing a real world problem in the thesis.

In this context, the aim of conducting research in the field of CAD/CAM technology was thus combined with the idea of working with a building construction material. The Portuguese context and the lack of research in the field led me to consider cork, which unquestionably presented a set of features that yielded interesting research questions. Moreover, at a global scale, this option became reinforced by the recent growth of a general consciousness about the world’s severe ecological and climate threats. At a time sustainability ceased to be just a buzzword and became a global concern, studying a natural and recyclable material like cork became an additional motivation for the present research.

Jose Pedro Sousa PhD Dissertation, IST-UTL

1.2

Chapter 1 Introduction

5

SCOPE

The research subjects of this thesis are inscribed the following three main areas, in which a subset of particular interests and topics define and narrow the scope of the research. 

architecture



digital technologies



materials

Focusing on rethinking the application of cork in architecture through the use of CAD/CAM technologies, the central problem of this thesis2 can be found in the intersection of these subjects, as the following diagram illustrates. [Fig. 1.04]

Figure 1.04 Diagram of the thesis scope.

Dictating the structure of this thesis3, each of these three main areas of inquiry broadly corresponds to a specific chapter. In brief, following the present chapter, the general area of architecture, its practice and interests, is discussed in Chapter 2. The general area of digital technologies is reviewed in detail in Chapter 3. Specifically dedicated to cork, the general area of materials unfolds in Chapter 4.

2

See 1.3 of the present chapter.

3

See 1.6 of the present chapter.

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Chapter 1 Introduction

As illustrated in the diagram above, the Chapter 5 puts in practice a set of experiments to which the previous three areas of interest converge. This chapter leads to the global and transversal conclusions of the thesis, which are presented and discussed in the Chapter 6.

Each chapter includes its own references list, with the goal of facilitating to grasp the frame of disciplinary references informing it. In short, while the background on the architecture field is drawn from the theory and practice of the discipline itself, the fields of digital technologies and cork mainly gets their information background from the scope of external disciplines: the former from mechanical engineering and industrial design, and the later from materials science and engineering.

1.3

RESEARCH PROBLEM

The thematic structure described above, helps to draw the context within which the central research problem is formulated and investigated.

After being solely rooted in crafts and, more recently, standardization paradigms, architecture is facing today new production possibilities related to geometric freedom and mass customization. A look into contemporary architecture reveals that many of the most significant built works around the globe result from an increasing interest in exploring unique forms and constructive solutions that could be hardly conceived and materialized a few years ago. Subjacent to this tendency, there is the conviction that the extensive use of computer technologies from design conception to building construction has been supporting and stimulating such creative endeavors.

This fact is pointed out by Kolarevic when he claims that “the Information Age, like the Industrial Age before it, is challenging not only the way we design

Jose Pedro Sousa PhD Dissertation, IST-UTL

Chapter 1 Introduction

buildings, but also how we manufacture and construct them”4. Arguing that the use of digital technologies has expanded the world of design and material opportunities, this thesis investigates the subjacent CAD/CAM technologies and processes that have been supporting such an increase of geometric freedom and flexibility in the production processes, and influencing the exploration of other design interests, such as mass customization, ornamentation or performance. [Fig. 1.05]

Facing this context of non‐standard exploration, the building materials’ industries cannot remain indifferent. Their success and competitiveness depends on their capacity to offer innovative products and services that are capable of responding to current architectural interests, but also, in a proactive way of developing and launching original and attractive solutions.

Surpassing standardization, the market have assisted to the emergence of an increasing number of new artificially designed materials (e.g., engineered composites and synthetic materials) but also to the rethinking of existing ones.

Regarding this last case, this thesis investigates how the exploration of CAD/CAM technologies by architects and industries have allowed the expansion of geometric and expressive possibilities of traditional materials (e.g., concrete, metals, glass, stone or wood). As a result of such technological strategies, architects have remained interested in working with these materials, independently of the uniqueness an unconventionality of their architectural design proposals.

In this scenario, and considering its meaning for the Portuguese economy and the global emerging interest in natural materials, this thesis investigates the case of the cork industry. Among the wide range of cork products, pure cork agglomerate is the one that has traditionally been employed in building construction. However, with the overall industry organized around the production and commercialization of cork stoppers, pure cork agglomerate is a slow innovation territory that is still rooted in mechanical and mass production processes based on standardization. The resulting monotonous 4

See: Kolarevic, B. (2001): “Digital Fabrication: Manufacturing Architecture in the Information

Age”, in W. Jabi (Ed.), Reinventing the Discourse, Proceedings of the ACADIA 2001 Conference, pp.

268‐277, Washington DC.

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Chapter 1 Introduction

catalogue of products, associated to the long‐time understanding of pure cork agglomerate as an insulating material for hidden and interior applications, has strongly limited its potential for becoming an interesting material for architecture.

Nonetheless, the observation of recent and successful applications of pure cork agglomerate as an exterior building facade material, initiated with Álvaro Siza’s Portuguese Pavilion for the EXPO 2000 in Hannover, have opened a new field of application, which represents a major challenge and opportunity for the cork industry. Using this natural material in a visible way to define the shape and image of buildings marks the entrance of pure cork agglomerate in a design territory where both architects and the industry traditionally puts their best efforts on. However, the affirmation of this material in this scenario cannot simply rely on the evidence of its unique natural properties. Realizing current architectural interests, the interesting opportunity launched by using pure cork agglomerate as a visible material can only be fully exploited if new geometric possibilities and material effects are also researched.

In this context, and inspired by what is happening with other traditional materials, the central problem of this thesis is: 

to investigate the hypothesis that the use of CAD/CAM technologies can play a driving role in the innovation of cork applications in architecture.

Subjacent to this question, it is argued that: 

in case digital technologies permit attaining higher levels of geometric freedom and mass customization in the production process, pure cork agglomerate can definitely have a renewed interest for architecture, which can trigger interesting economic and disciplinary implications.

Jose Pedro Sousa PhD Dissertation, IST-UTL

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Chapter 1 Introduction

METHODOLOGY

The research methodology was driven by two main premises. Tied to the scope of this thesis, the first premise was the need for developing multidisciplinary work, and it required: 

going beyond the boundaries of architecture to learn about digital technologies and cork in adjacent areas, like mechanical engineering and materials science;



looking outside of Portugal for finding and contacting with other sources of relevant knowledge, competences and references.

Inherent to the thesis problem, the second premise was the convergence between theoretical investigation and practical experimentation, which implied: 

exploring the relation between the academic environment and the reality of the industrial world, for formulating, developing and testing ideas.

In accordance to these premises, the following diversified set of activities was strategically defined to feed and support research development in its different domains: 

Academic e.g., course attendance, teaching and independent research;



Practice e.g., projects, experiments;



Contacts e.g., buildings, companies, specialists;



Divulging e.g., papers, publications, communication, lectures and exhibitions.

The development of these activities was conveniently scheduled for matching the initial research plan: from the initial learning of general theoretical references and acquisition of technical skills, towards the final execution of specific and practical experiments. The methodology steps are summarized in following.

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Chapter 1 Introduction

The starting point of this research was the general study of architecture and digital technologies, to survey the state of the art. With this goal, a curricular plan was defined at the outset, involving independent research and course attendance.

Due to the limited information available in Portugal, research periods at MIT and UPenn were fundamental for getting access to a wide range of both the oldest and more recent bibliographic references on these subjects. Once there, it was also possible to visit libraries in other schools (e.g, engineering, computer science, fine arts) and in other academic institutions (e.g., Harvard GSD, Columbia U.). The possibility of consulting Master and PhD thesis on related subjects, and also early 20th century American bibliography on cork5, were two key opportunities.

At the same time, the courses taken at MIT and IST‐UTL, and additional short workshops in other places, allowed me to improve personal skills in digital design and manufacturing technologies and processes, which were important for undertaking future practical experiments. Theoretical research could thus be supported and fed by hands‐on knowledge.

With this education and research experience, the thesis scope and problem became progressively focused on the material opportunities emerging from the use of CAD/CAM technologies in architecture. Materializing the first methodological premise, the convergence of different subjects promoted the creation of an Advisory Committee composed by an architect, a mechanical engineering and a materials scientist.

Then, the research work evolved also out of the academic context, through works with digital technologies developed in a professional practice, and contacts with materials and manufacturing industries.

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The United States of America played a leading role in the world cork industry by the end of

the 19th century and beginning of the 20th century, which made them the most important source of information on the subject in those times. This is further explained throughout the Chapter 4 of this research.

Jose Pedro Sousa PhD Dissertation, IST-UTL

Chapter 1 Introduction

On the one hand, through the parallel practice of ReD6, it became possible to explore and test digitally conceived design ideas in real scenarios. With this approach, alternative applications for a wide range of materials (e.g., concrete, wood, metal, acrylic) were investigated, driving the production of customizing building solutions. Committed to their physical execution, the studio acted as a laboratory for the implementation in practice of several digital design (e.g., parametric modeling, scripting) and manufacturing technologies (e.g., additive, subtractive and formative fabrication processes).

For this reason, the experience with ReD became an invaluable source of ideas for inspiring the development of this research, as well as a laboratory for improving technological competences. Both the state of the art review and the specific research on cork have strongly benefited from experience.

On the other hand, with the material’s interest focused on working with cork, it became necessary to establish a direct contact with the industry. With AMORIM, it was possible to visit in‐loco production factories and know more about the nature of the material and its applications from specialists. As a result, this experience led to the selection of pure cork agglomerate as the case‐study material for this research, providing knowledge concerning both the potentials and limitations of its production and application in architecture.

Throughout this intermediary period, other complementary tasks were conducted to guide the evolving research. For instance, the teaching of courses and short workshops on the use of CAD/CAM technologies served as laboratories for practical experimentation and learning of their potentials and limitations. At the same time, the divulging of research results in publications, conferences, and exhibitions permit to gather direct feedback from researchers and industry people alike. At this level, writing became an important task for organizing and settling down research ideas. In addition, specific parts of the research were discussed with specialists from diverse fields, who gave their critique and advice. Finally, visiting landmark buildings and companies in loco was another important source of insight that enriched thesis development.

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Co‐founded with Marta Malé‐Alemany, the studio ReD, Research+Design, was specifically

dedicated to the implementation of digital technologies in practice. Based in Porto and Barcelona, it developed a series of international projects with a permanent critical interest on new conceptual and material opportunities emerging from the digital technological condition.

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Chapter 1 Introduction

Demonstrating the second premise of the research methodology, the final part of the research was mainly dedicated to the development of experiments with pure cork agglomerate, using CAD/CAM technologies. The learning and conclusions obtained through the previous research activities informed the definition and goals of the practical tests. Conducted in manufacturing laboratories and shops of academic institutions and industrial companies, this research work allowed me to address the thesis problem by testing different fabrication technologies and evaluating the behavior of pure cork agglomerate under given fabrication conditions. In many of these experiments it was possible for me to control and execute them directly, which was instrumental for gaining a deep understanding of the fabrication issues involved. In this context, the comparison of the fabrication experimental set ups with the produced parts became the basis for the conclusions of this thesis.

Finally, the writing of the thesis benefited from some early writing activity and other materials collected and published along the research. Its organization, which will be explained bellow, expresses some aspects of the methodology just described.

1.4

CONTRIBUTIONS

The research carried out for this thesis resulted in a diverse set of contributions.

Directly emerging from its research problem, the main contributions of the thesis are the following: 

At a global scale, and within the architectural realm, the discovery and suggestion of new possibilities for architects using a traditional material like pure cork agglomerate to address their design interests, taking advantage from its unique ecological and functional properties.

Jose Pedro Sousa PhD Dissertation, IST-UTL



Chapter 1 Introduction

At a local scale, and within the industrial realm, the assessment of the current state of the pure cork agglomerate industry from an architect’s perspective, and the proposal of strategies to implement CAD/CAM technologies for expanding its productive possibilities, to go beyond its current limitations and match current contemporary architectural concerns.

At a secondary level, the research work developed for this thesis brought about other complementary contributions, namely: 

a synthetic historical overview of architects’ interest in using digital technologies in architectural practice, and a critical discussion of its real impact;



an updated review of the current digital design, engineering and manufacturing technologies (CAD/CAE/CAM) that can be potentially interesting for building construction;



the demonstration of cork and, more specifically, of pure cork agglomerate, as an invaluable natural material with an interest for architecture and building construction that should not be ignored in the present times;



The description and illustration of a set of subtractive fabrication experiments with pure cork agglomerate, involving the use of different CNC machines and the testing of diverse fabrication parameters to accomplish specified design goals, which can serve as a guide for architects and fabricators wishing to digitally work with this material.

1.5

ORGANIZATION

This thesis is organized into six chapters, including the present one, and the last one where the general conclusions of the investigation are presented and discussed. The four chapters in between are dedicated to specific research subjects and they include partial concluding remarks, that function as step stones towards accomplishing the goal of this thesis. Following, there is a brief description of each chapter’s content.

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Chapter 1 Introduction

Chapter 1 – Introduction This chapter presents the main motivations that led to the development of the thesis and identifies its central problem. Presenting the methodological approach of the research, it outlines the contributions of the thesis and describes its structure and organization.

Chapter 2 – Architecture and Digital Technologies Defining the disciplinary background of the thesis, this chapter investigates the use of digital technologies in architecture and its impact on representation and construction possibilities. In doing so, it proposes an historical perspective about the integration of computers in architecture, built from the perspective of the key‐interests that have led architects to adopt them in practice. By discussing its impact in materiality, it argues that an investment in digital technologies on the behalf of architectural practice is the key factor for overcoming design and material limitations imposed by craft and mass production paradigms that ruled the construction world before the information age.

Chapter 3 – Review of Relevant Digital Technologies This chapter provides a brief review of the state of art of digital technologies for assisting design, engineering and manufacturing processes in architecture. Having learnt from the previous chapter that the extended space of architectural possibilities depends on the representation and construction methods selected by the architect, this review focus its attention on the systematization of those technologies that are thought of being more capable of promoting the entering in a era of new production possibilities.

Chapter 4 – Cork and Architecture Encouraged by verifying that digital design and manufacturing technologies can open innovative applications for existing materials in architecture, cork, and more specifically, pure cork agglomerate, is selected as a case‐study material for developing a more in‐depth theoretical and practical research.

Thus, this chapter is dedicated to research its productive processes, properties, products and applications with the intention of inquiring into the

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relevance of this material for the building construction industry in the present world. Recognizing current production limitations, it envisions the interest of using CAD/CAM technologies to rethink its application in architecture.

Chapter 5 – CAD/CAM Experiments with Pure Cork Agglomerate By proposing a specific strategy for implementing CAD/CAM technologies in the cork industry, the present chapter is dedicated to document a series of practical experiments with pure cork agglomerate carried out with subtractive fabrication technologies. The subjacent goal is to test the capacity for achieving a greater degree of geometric freedom and customization in its products, at the level of 2D shape, surface texture, and 3D form possibilities.

Chapter 6 – Conclusion While each of the previous chapters include concluding remarks regarding each specific research topic, this last chapter is dedicated to present the general conclusions emerging from the investigation as a whole. The possibility of rethinking the application of pure cork agglomerate in architecture through the use of CAD/CAM technologies is discussed according to the technological framework provided by the thesis. Further research avenues are also presented and discussed.

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Chapter 2

Architecture and Digital Technologies

2.1

INTRODUCTION

Unfolding around the creation and the production of an object that does not exist a priori, the practice of architecture oscillates between two main actions or moments. They can be denominated as: 

the Design – involving representational tasks for the conception, development, analysis, and communication of a design solution.



the Construction – involving materialization tasks towards the physical manifestation of a design object.

When Mitchell (2001: 353) states that “architects tend to draw what they can build, and build what they can draw”, he is defining a bi‐directional cause‐ and‐effect relation between those two actions. This suggests deducing the following reasoning. As an hypothesis, it seems that the confirmation of significant transformations in the nature of any of those moments will necessarily expand the world of architectural possibilities by opening new conceptual and material opportunities potentially capable of affecting the built environment production [Fig. 2.01].

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Figure 2.01 The influence of design and construction fields in defining the space of architectural possibilities.

Understanding then influence of technology and culture, the relation between design and construction have seemed stable throughout history, with the exception of three main periods where it was strongly questioned.

The first of those moments happened in the 15th century with the Renaissance, and its relevance is undeniable. It was during this period that architecture emerged as a profession closely linked to design tasks and separated from construction. Then, the Industrial Revolution of the 18th century supported a paradigm change in the production means, which directly affected the construction logics and possibilities and, therefore, architecture itself. In both situations, the temporal distance that separates us from those periods has allowed the objective production of scholar studies shows their real importance.

More recently, by affecting simultaneously the design and construction realms, the impact of digital technologies in architecture, particularly over the last 15 years, suggests the possibility that we are crossing today a third moment where decisive changes are taking place. Indeed, computers are an omnipresent reality in any architectural office today, which cannot be detached from the broader picture of the current technologic and cultural transformations. The rise of the digital information and communication technologies since the end of the Second World War have been supporting

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the emergence of a Post‐Industrial era. Being called as the Information Age1, it carries a paradigm change in many levels that cannot leave indifferent the discipline of architecture.

As this is the period that defines the disciplinary background of this dissertation, the present chapter intends to offer an historical perspective about the integration of computers in architecture. Discussing the evolution from an analogical (i.e., before the information Age) to a digital condition for the developing of architectural projects, it identifies the interests that led architects to adopt them in practice. By taking Mitchell’s equation as a reference, it wants to contribute for an evaluation of the computer’s potential to impact the discipline through a careful interrogation of its capacity to interfere in the realms of design and construction.

2.2

THE ANALOGICAL CONDITION

Reflecting about the nature of design in architecture, Kalay (2004: 7) claims that “buildings, prior to the Renaissance, were constructed and not planned”.

Agreeing with this view, Terence Riley (McQuaid, 2003: 11) argues that this fact explains why the “history of architectural drawings is considerably shorter than the history of architecture”.

1

Among scholars, it is possible to find many suggestions to define the world today. One of the

widely accepted ideas describes the emergence of a “Post‐Industrial Society”. It was presented in 1978 by Daniel Bell, a sociologist and professor at Harvard University, in his book The Coming of the Post­Industrial Society. The main idea of this concept describes the move from an Era based on manufacturing to one based on services. In this scenario, information plays a dominant economic, political and cultural role that leads to the idea of the “Information Age”.

To establish a parallelism to the previous Agricultural and Industrial revolutions, this period is also often called as “Information revolution”, supported by the new digital technologies of information and communication.

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The Middle Age

For instance, during the Medieval Age in Europe, military and religious construction was an important focus of attention of the building activity. The need to produce better fortified castles and cathedrals, developed masonry construction and triggered the emergence of trained craftsmen, like masons and carpenters, with a deep knowledge about materials, tools and techniques of their craft. This practical expertise was so fundamental for the quality of the work, that their activity was surrounded by secrecy, and frequently kept within the same family, transmitted across generations from father to son. As stated by Addis (2007: 87), “it was forbidden to divulge any information outside the mason’s lodge, either to other masons or non­masons”. In this context, the image of the architect of this period corresponds to that of the master‐builder that was directing the construction on‐site, orienting the team of highly‐skilled craftsmen2 [Fig. 2.02]. His commitment with that act was so profound that he often ended up living in the construction site3. In those days, W. J. Mitchell (Kalay, 2004: ix) notices that “there was no intellectual, managerial, or legal need for the sort of comprehensive design documentation as we know today”.

As building construction could take several generations to be completed, the architect’s creative role was expressed through construction activity. For instance, although the design of a cathedral could start from some geometric principles, the evolution of its construction was mainly decided in‐loco, frequently influenced by decisions taken through the observation of its progress4. Design and construction happened thus simultaneously, sharing the same geographic space of the construction site [Fig. 2.03]. With the absence of extensive representations, the architect master‐builder was the

2

This idea is described by Harves (1971: 33), who accounts for the absence of the figure of the

architect as we know today explaining that “from the eleventh century if not earlier, virtually all architecture and most sculpture was produced by laymen with a training in craftsmanship”.

3

Studying the move from craft modes of production to industrial ones, Sebestyén (1998: 7)

writes that “the master mason was totally committed to the building in which he was engaged. He not only designed it and led its construction, but in many cases he even lived on the site; indeed, it is no exaggeration to say he lived for his building”.

4

About this on‐site dynamics, Kalay (2004: 7) explains that “facades were derived by way of

deducing the elevation from the plan, applying the master builder’s “trick” – a system of proportion based on triangles or squares – with the help of a compass and a ruler. Much of the building was unplanned or undesigned, in the modern sense of the term, other than templates for columns and vaults, there were no drawings and no models to follow”.

Figure 2.02 Construction site in the Medieval Age.

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only one with a mental vision of the building, which became more and more focused through its development, by mastering its own intentions, existing material resources and the practical contribution of craftsmen’s talent. As Harves (1971: 9) resumes, “it is due to the close identification between efficient craftsmanship and aesthetic perception during the Middle Ages that the art of the period has so intense an interest”.

Figure 2.03 The convergence between design and construction in the Middle Age.

The Renaissance

The transition from the middle ages to the modern age, which took place with the Renaissance in the 15th century, brought important changes in many aspects of human activity. The rediscovery of the artistic values from the classical Greece and Rome motivated the elevation of humanist values, while important technical developments promoted industry and science.

The focus of this cultural revolution was centered initially on the economically prosper Italy, and it naturally affected the realm of architecture.

According to Addis (2007: 119), people involved in building design were trained in a system of workshops based on the combination “of some scholarship learning with apprenticeship in practical skills, such as painting, sculpting in stone, and metalworking in bronze”. While this practice could seem inscribed in a logic of continuity from the craftwork of the Medieval ages, it promoted a broader form of education supporting the emergence of the renaissance artist skilled to master several different practical fields.

Educated in this fashion, Filippo Brunelleschi (1377‐1446) was a military engineer who became one of the most preeminent figures of this period, together with other universal men like Michelangelo or Leonardo da Vinci.

His profound interest in construction issues was clearly demonstrated in his simultaneously inventive and detailed engineered approach to the construction of the Dome of the Santa Maria del Fiore Cathedral.

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Simultaneously, in a different way, other group of people involved in building design was receiving a classic and humanistic education in schools, covering theoretical subjects like architectural history. Without the practical experience of the workshops, the learning processes were mainly focused on books and verbal discussion, while the practical skills were centered in the practice of drawing. In this context, architecture as a profession emerged far from the construction site, and its public recognition became facilitated by the body of specific publications written by architects5.

Among them, Leon Battista Alberti (1404‐72) was one of the most acclaimed architects of this period. He wrote the important De re aedificatoria, which was published in 1485 to “clarify Vitruvius, and provide a contemporary interpretation for those patrons wanting to commission buildings in the newly fashionable classical style” (Addis, 2007: 127). From his superior position, Alberti promoted the practice of drawing in architecture as the means to conceive and describe future buildings. Both as a man and as a professional, the architect could thus ascend to a higher – intellectual – status, which socially promotes and distinguishes him from those carrying the practical – manual – works of the construction. Separated from that moment, "architects ceased to be technicians supervising the construction project on­site and became designers, who expressed their professional skills through drawings” (Kalay, 2004: 8). As noticed by Tavares (2004: 92), the result was “a definitive clarification that distinguishes the artist from the craftsman, which places architecture as an intellectual category and assigns to “design” the central role of the architects action”6. Maintaining this position, T. Riley (McQuaid, 2003: 11,12) highlights that: “for the first time architects and artists could accurately plan and depict a proposed building or work of art –in whole or in its parts­ by mastering the skills of drafting and perspective drawing. More important, drawing allowed the pursuit of the theoretical problems that would give architecture of the Renaissance its defining characteristics: orderliness, a sense of scale, formal unity, and stylistic refinement.”

5

The invention of printing technology in the 16th century allowed the reproduction of texts and

images. This factor accelerated the circulation of architectural publications thus contributing for the public recognition of architecture as an autonomous profession.

6

Translation from Portuguese to English done by the author.

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With the discipline of architecture and the creative processes unfolding mainly on the representation level, the communication of design ideas for their physical execution required the creation of drawing conventions, like scale drawings and physical models7. The introduction of the perspective by Filippo Brunelleschi was another major invention very well accepted in the field. Curiously, this innovation seemed to symbolize the elevation of the man and the architect itself, by placing his vision at the core of the spatial control and evaluation. The progressive ascension of the role of the conventional drawing in architecture can be witnessed in other major influent architectural books that followed Alberti’s. Respectively published in 1537‐ 40 and 1570, both Sebastiano Serlio’s Sette Libri dell’Architettura and Andrea Palladio’s I Quattro Libri dell’Architettura made extensive use of illustrations –plans, sections and elevations‐ to convey architectural ideas and knowledge.

However, as Addis (2007: 149) points out: “the technical expertise needed to execute buildings could not yet be communicated in books; this still had to be learned in the construction site. In the hands of scholarly architects, the Renaissance classical style was thus largely a matter of appearances: facades and ornamental detailing.”

Since then, and almost to the present days, very few things seemed to have changed in the nature of architectural practice. For Carranza (2007: 153), today, “despite substantial changes in the technology employed, the architect’s craft is still placed on the mediating plane of the drawing, over which he or she has apparent command”. Although it is possible to find exceptions to this generalization, what is important to retain is the fact that design and construction started to be considered as separate moments. Played by different building specialists and mediated by systems of representations based on conventions, this condition seemed to have persisted without major interferences until today [Fig. 2.04].

7

Curiosly, Y.E. Kalay explains that “the technical evolution of scale drawings has, paradoxically,

increased the importance of scale models, because clients became less able to interpret the growing abstraction of architectural drawings” (Kalay, 2004: 8).

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Figure 2.04 The separation between design and construction with the Renaissance.

The Industrial Era

At another level, the Industrial Revolution, with its roots in the England of the 18th century, and the many social and technological developments that took place afterwards, established a rupture with the modes of production based on craftwork. The competence of the machine in replacing manual labor (mechanization), the practice of scientific management strategies (Taylorism) and the implementation of the assembly line (Fordism) were some of the main factors that dictated the industrial paradigm of mass‐ production based on standardization.

Facing those developments, Callicot (2001: 35) states that some artists and designers started to question the capacity of the craft methodologies to answer the ongoing serious social transformations and requirements. Seeing craft work threatened, some important figures like John Ruskin and William Morris stayed firmly defending the “irreplaceable charm of the singularity of the crafts product”8, as romantically described by the architect and theorist Giedion (1995: 88). Nonetheless, the impetus for changing that was evident in almost every aspect of the society also prevailed in architecture, mainly from the 19th century on. Thus, exploring the advantages of economies of scale, industrialization based on materials like cast iron, glass and later steel and reinforced concrete, emerged, following rules of geometric and dimensional normalization. At the same time, the introduction of improved transportation systems, like trains, supported the manufacturing of building components far from the construction site, opening up the possibility of pre‐ fabrication.

8

Personal translation from Portuguese to English.

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Observing this scenario, it seems plausible to accept that the distance between design and construction increased. In a certain way, within this paradigm, design development appears to have no role in the material decisions that were being taken by industry to fulfill its standardization and mass‐production ambitions. Instead of conceiving customized building elements, architect started to select the most convenient solutions from catalogues with standard building construction products.

Nonetheless, the creative spirit of architects envisioned ways to overcome this limitation, and used this constraint to develop new design opportunities.

The rationalization of building components, together with the physical properties of the industrialized materials, supported the emergence of new architectural typologies like the railway station, the bridge or the exhibition fair pavilion [Fig. 2.05]. Looking into these projects, symbolizing the zeitgeist, it is possible to verify another interesting change. With the design prescription of standard components and its pre‐fabrication, the building

Figure 2.05 Crystal Palace, London, 1851.

Designed by Joseph Paxton to house the Great Exhibition in London, its huge and pre‐

became an assembled entity rather than a constructed one. In the

fabricated cast‐iron and glass

construction site very few things could remain to be created or decided.

structure made it an icon of

Thus, while in the Renaissance the construction of buildings still continued to

of the industrial revolution

rely on the talent of craftsmen to materialize the architects designed ideas, the Industrial Era, the assembly of buildings in the construction site reduced the need for specialized craft workers.

In this period, the architect’s progressive loss of control over the construction processes was reinforced by a new event ‐ the emergence of the figure of the engineer and the constructor in the transition from the 18th to the 19th century9. Due to their pragmatism and technical knowledge about materials and industrial processes, both professions contributed for a social perception of the architect as an artist10. Concerning the architectural typologies mentioned before, some engineers competed with the architects for the client’s preference and the professional responsibility for developing

9

Jaques Heyman book titled “The Science of Structural Engineering” (1999) provides a concise

reference about the history of engineering as a profession, especially in the first chapter. In his 1928 book called “Building in France. Building in Iron. Building in Ferroconrete”, Siegfred Giedion acknowledges the appearance of the constructor in the XIX century and describes its impact on architecture as a profession. This book was consulted in a 1995 edition published by the Getty Center for the History of Arts and Humanities.

About the engineer, see Jacques Heyman (2). About the contractor see Siegfred Giedion –

10

Building in France.

the architectural production period.

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those projects. This became so evident during the 19th century that led Giedion (1995: 94) to state in 1928 that: “unconsciously the constructor assumes the role of a guardian in the nineteenth century (…) [he] presses for a design that is both anonymous and collective. He renounces the architect’s artistic bombast (…) we sense how the “artist­architect” feels his privileged position menaced, out of which grows increasingly spasmodic emphasis on his “artistry”.”

Since then, the appearance of more and more participants specialized in specific aspects of the architectural project has contributed for shrinking the territory of architects’ action. In a more and more complex and exigent world11, standardization became the dominant paradigm in the construction industry throughout of the 20th century, serving as an efficient strategy to deal with the increasingly strict requirements about the quality and performance of building products and technical solutions.

The Information Era

In this context, the emergence of the so‐called Information Era of the end of the century seemed to challenged the analogical conditions sustaining the practice of architecture [Fig. 2.06]. The appearance and diffusion of the computer promoted a move from an analogical condition to develop architectural projects, based on physical design tools and mediums, and manual/mechanical means of construction, to a digital condition, sustained by computer‐driven design and manufacturing technologies, which opened new design and construction possibilities, as it will be discussed next.

Figure 2.06

Architect at his drawing

board. The analogical

development of the

condition for the architectural projects just One factor that contributed for a greater complexity in the XX century world is the emergence

11

of globalization movements that radically affected social, economic or politic dynamics, and merged local with global logics. In this context, society became increasingly more exigent, for example, about the responsibility and quality of the commercial products leading to the emergence of international quality parameters for markets regulation, producers responsibility and consumers protection.

before the Information Era.

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2.3

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THE DIGITAL CONDITION

The rise of the Information Age, as a new decisive period of human history, is intimately linked to the emergence of digital technologies, initially centered on a single machine – the computer. Deriving from the Latin computare, the computer has its roots associated with the execution of calculation tasks.

Since the antiquity, this concept has been implemented in many physical instruments, like the abacus, but the principles of the modern computer, as we know today, are found in the 19th century, in Charles Babbage’s unbuilt works called “Difference Engine” (1822) and “Analytical Engine” (1834).

However, only with the end of the 1930s became possible to technically move from an analog to a digital mode of computation12. According to Wurster (2002: 18‐19) the advantages of this alternative way of information processing lied on its speed, flexibility, programming and data storage capacities. Composed by hardware and software, the digital computer was thus different from a calculation machine. While the later is functionally pre‐ determined and closed, the former is a generic machine that is open and ready to be programmed by a user to perform a myriad of complex and custom tasks, based on calculation procedures.

It was in this period of debate, between analog to digital computation, that appeared the first relevant application of computers in the construction field.

It happened in the discipline of structural engineering, probably due to its practical and theoretical procedures very linked to calculation. During the construction of the Sydney Opera House (1959‐73) designed by John Utzon, the engineers at Ove Arup had to use computational processes to deal with complex problems issued by the singular formal features of the project.

According to David Taffs, this engineering firm pioneered the use of digital technologies in construction, while playing consequently an active role in the evolution in the field of computation. At that time, Over Arup worked with

Figure 2.07

historical computers such as the Ferranti Pegasus 1 [Fig. 2.07], and had to

The Ferranti Pegasus 1 used

write their own computer programs to study the curved geometry of the

complex calculations of the

cupolas and to calculate the glass walls of the building [Fig. 2.08]. The

Developed by Karl Zuse (1910‐1995), the Z3 prototype was a decisive step towards the

12

consolidation of digital modes of computation. Until then, computers were based on analogical processes, sustained by numerical measurements of mechanical, electric and hydraulic phenomenon.

by Ove Arup to perform the Sidney Opera House.

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computer contribution for the success of this work was so decisive that led Ove Arup himself and his partner Jack Zunz to affirm that “it is felt the shells could probably not have been built without the use of computers. We could not have produced the mass of information, let alone the analytical work, necessary to erect the building in the time available” (Watson, 2006: 85).

Although the project suffered some formal changes motivated by the intervention of engineering, the interest that presided over the integration of

Figure 2.08 Design and construction challenges of the Sidney

digital technologies was analytical. It was mainly focused on the realization

Opera House. The shape of

of complex engineering calculations with a high degree of precision to

the roof evolved overtime

accomplish the materialization of Utzon’s vision13.

and ellipsoid shapes, to the

from freeform, to parabolic final spherical geometry.

Centered in mathematical calculations, this kind of approach could hardly captivate designers. As architects are linked to a culture of representation dependent on physical medium and tools (e.g., paper, pencil, models) they stayed disconnected from the infancy period of the digital computer. This situation changed with the evolution of in the 1970’s of human‐computer interfaces towards graphic output devices that offered geometric In this scenario, the architectural design and building construction processes still follow

13

analogical procedures. It is possible to consider that they are not really affected by the introduction of digital calculations on the engineering side.

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representation possibilities14. Although technically data calculations support the edition and visualization of images on the computer screens, it was this possibility of representation itself that seemed to motivate architects to use digital technologies. Thus, the consolidation of the idea of the computer as a representation machine, supplanting the concept of a calculation machine, was crucial to promote its disciplinary assimilation, and marked the beginning of the exploration of its potentialities.

Oscillating between these two dimensions – calculation and representation – many different interests have driven architects to adopt computers in practice since its origins approximately five decades ago. Considering their possible overlapping in time, it is proposed an historical perspective of its disciplinary assimilation structured by the following key‐interests: 

Phase 1: Productivity



Phase 2: Visualization



Phase 3: Conception



Phase 4: Construction

Due to its indirect influence in the design and construction processes, this overview is followed by a complementary comment about: 

The rise of computer networks

2.3.1 Phase 1: Productivity

The first period of the computer’s integration in practice was characterized by a general interest in achieving higher levels of productivity in the production of design drawings, when comparing with the possibilities offered by traditional analogical tools for representation [Fig. 2.09].

14

The declining of computer prices was also a determinant factor for computers integration in

architectural practice. But in cultural terms, the emergence of computing representation capabilities is the main motor for the disciplinary interest in its assimilation.

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COMPUTER

Figure 2.09 Phase 1: Productivity.

Productivity

(2d drafting)

The first computer applications in the discipline of architecture can be found in the sixties. In a publication of that period, Harper collects a set of contributes that illustrate some of the first digital approaches to the practice during that decade in architecture and engineering15. At that time, the dominant vision considered the computer an helpful calculating machine that speeded‐up and automated mathematical tasks like the control of building costs. The benefits of this tool were suggested by Charles Thomsen (Harper, 1972: 197‐198) when he claimed that “the computer promises to give architects a control over the restrictions of function and cost (…) like a sculptor knows the limitations of his clay or the layers of his marble block”. Going further with his opinion, he then proposes that “the concept of economy starts to be by itself a valid expression of aesthetics”16. Nonetheless, given that in architecture these calculation tasks are usually external to the representation and construction processes, which are the places where conception and materialization traditional occurs, it is difficult to agree that the greater efficiency introduced by computer in the performance of calculations has produced a direct impact on the discipline as some were dictating.

In this context, the PhD thesis submitted in 1963 by Ivan Sutherland at the M.I.T. is frequently mentioned as the decisive breakthrough for the beginning of Computer‐Aided Design (CAD) technologies. Titled Sketchpad, a Man­ Machine Graphical Communication System, this work was based on the observation that “most interaction between men and computers has been slowed down by the need to reduce all communication to written statements that can be typed”. With irony, the author added that “we have been writing letters too rather conferring with our computers” (Sutherland, 1963: 8).

This book was consulted and referenced in this dissertation in its spanish version, published

15

in 1972, and titled “Aplicaciones de las Computadoras en Arquitectura e Ingenieria”.

Personal translation of this thesis’ author from Spanish to English.

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31

Indeed, there was an opacity that kept away from computers anyone non‐ specialized in its usage. Thus, Sutherland envisioned that the development of a graphic interface could open up “a new area of man­machine communication” that could potentially be interesting for other disciplines more connected to creative design tasks, like architecture [Fig. 2.10]. The Sketchpad work influenced the further emergence of other computer programs, which, by allowing the rigorous creation, flexible edition and efficient storage of drawings within the digital medium, supported the

Figure 2.10 Ivan Sutherland and his

possibility for computer‐aided design practices.

graphic‐based computer

interface Sketchpad.

Outside the academic research environment, the larger architectural firms

were the ones that could afford to incorporate computers in their practice during the 1960’s and the 1970’s. Some of the main reasons were: 

the high‐cost of the equipment, which was an obstacle for small firms with scarce economic possibilities;



the large dimensions of computers at that time, which required large physical spaces to accommodate them;



few and primitive software solutions, which frequently forced the users to program and create their own customized tools.

The particularities of such context were extensively mapped by Alfred Kemper in his book called “Pioneers of CAD in Architecture” (1985). There, focusing on the American scene, around 60 firms and 12 architecture schools present their own story about the reasons that led them to incorporate computers in practice, and their own CAD methodologies [Fig. 2.11]. In Kemper words (1985: 1), these were: “the architects/engineers who had the courage to buy half­finished systems and had the fortitude (or persistence) to make these half­ finished systems work. They showed the vendors what our profession needs. They are indeed the pioneers who layed the foundation for CAD in architecture”.

Skidmore Owings & Merrill (SOM) from Chicago and New York, HOK from St. Louis, Albert C. Martin from Los Angeles, Perry Dean & Stewart from Boston

Figure 2.11

or Everett I. Brown Company from Indianapolis were some of the first offices

Computer representations at

incorporating computers in their practice. Involving specialized people, they started devising their own computer programs either by writing new

BOHM, one of the architectural offices featured in Kemper’s book.

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software from scratch or programming extended capabilities to the available ones.

With the practice traditionally centered on three types of representations ‐ sketches, technical drawings and communication drawings [Fig. 2.12], architects started to recognize some advantages of the digital medium to assist in the production of the second. Besides calculating abilities, the drawing precision and the extreme facilities to correct, reproduce and store it in the computer memory became evident. Because drawing with the computer followed similar methodologies as with analogical techniques, the operative assimilation of the computer became easier. As a result of the introduction of CAD processes, architectural practices experienced a radical acceleration and a greater efficiency in the production of drawings, which essentially consisted in 2D representations for design documentation.

Figure 2.12 The conventional hand‐

Drawing Representations

drawing representations associated to the practice of

Sketch

Technical

For conception

architecture.

Personal and subjective graphic expression

For the development and construction Conventioned representation obeying to normalized graphic and interpretation codes.

Visualization

For presentation Universally understandable illustration, often realistic

In this scenario, the following question should be asked: to what extent did digital technologies, and the consequent increase of productivity, affect the nature of architectural practice?

As it usually happens, whenever a new technology is introduced its assimilation tends to imitate the precedent ones, and it takes some time to realize its specificities and expressive autonomy17. The integration of CAD systems did not deviate from this rule. Although the drawing board was replaced by the screen and physical tools by digital ones, digital drawing still followed the same rules followed in the production of analogical drawings Before finding their own aesthetic territory, photography tended to imitate painting and

17

cinema got inspiration in theatre. More recently, the early uses of email tended to follow traditional habits of mailing post.

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[Fig. 2.13]. Its goal continued to be the description of a design solution through a normalized system of 2D drawings to be ultimately presented in paper format. In this process, the conceptual dimension of the design project still relied on traditional strategies, like sketching or physical modeling. As this analogical condition still continued to be a determinant factor for creative possibilities, one can consider that the nature of the design process did not change at all with this partial digital interference. Without affecting also the realm of construction, it is possible to consider that architectural practice still continued to be developed in a linear fashion, from conception to construction.

Figure 2.13 Analog vs. digital drawings.

Despite the use of different tools and mediums, the representations by Leon von Klenze in 1822 (left) and the ones by Tod Williams in 2001 (right) share the same drawing’s logic and rules.

In this scenario, it is usually said that the “D” from CAD actually stands more for Drafting rather than Design. For instance, a common practice in architectural offices is that of the principal architect sketching the design concept and sending it for his collaborators to produce the correspondent descriptive 2D digital drawings. Reflecting about desired developments for CAD technologies in architecture, Chris Yessios (Kemper, 1985: 10) summarized that computers should: 

emphasize design rather than drafting;



integrate 2D and 3D representations;



be easy to use and adjustable to the traditional methods of architectural practice.

The need for less expensive computers to facilitate its diffusion should also be added to this list.

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2.3.2 Phase 2: Visualization

The second phase of the computer’s integration was characterized by the definite diffusion of computers in architectural practice and the starting of digital exploration of three‐dimensional modeling capabilities, mainly oriented for visualization purposes [Fig. 2.14].

Computer

Figure 2.14 Phase 2: Visualization.

Productivity

Visualization

(2d drafting)

(3d modeling)

The beginning of the 1980’s witnessed the emergence of radically cheaper and smaller computers. With the so‐called Personal Computer (PC), digital technology became affordable for smaller practices, and not a privilege of the big professional and academic institutions18. At the same time, the industry of commercial software for the construction industry had matured and started marketing a wider range of solutions19. Both situations enabled the world of architectural offices to finally embrace digital technologies in their practice, independently of their size or economic capacities.

In the mid‐80s, the development of 3D modeling software capabilities strengthened the interest in more sophisticated digital representations besides the production of 2D technical drawings20. With the digital modeling As observed by Tom Forester (1986: 1), the introduction of the microprocessor “has put

18

cheap computing power on the desks of millions”.

During the 80’s, the development of software ceased to be the result of private research

19

initiatives from big firms and academic institutions. Autodesk, probably the most important CAD technology company for architecture and construction, was founded in California in 1982 by a group of people guided by John Walker. In that same year it was released the first version of AutoCAD, which is the most popular software in the field nowadays. In 1985 Bentley Systems, another important company, was founded by Keith Bentley, releasing the also famous Microstation.

20

CAD software for mechanical engineering industry started to incorporate three dimensional

capabilities earlier than the one for the construction industry, because of its close relation with CAD/CAM production. Taking AutoCAD as a reference, the first time it integrated 3D capabilities was in 1985, when its 2.1 version was launched.

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of surfaces and solids, it became possible to assign graphical textures representing physical materials, simulate lighting conditions, either artificial or natural, or define visualization perspectives through the control of virtual cameras. Out of such comprehensive models, architects could render computer images and produce digital animations of their projects. In a more advanced way, other simulation technologies started to be investigated.

Virtual reality systems looked for more sophisticated experiences between man and 3D models, through the use of interactive interfaces and immersive environments21. However, due to the complexity and cost of that equipment, only research institutions could afford the integration of such systems.

Trying to synthesize, architects’ interests in exploring 3D digital representations can be summarized as being concerned with [Fig. 2.15]: 

the anticipation and visualization of an architectural object that does not exist, during its design development phase;



the digital reconstruction of an architectural object, historical or contemporary, for its documentation and study.

Figure 2.15 Renders for visualizing future buildings, like the Beijing Herzog & de Meuron’s Olimpyc Stadium (left), and historical projects, like the Giuseppe Terragni’s House on

the Lake (right).

In doing that, two different expressive tendencies in 3D digital modeling can be distinguished: 

the hyper­realistic – that aims the simulation of reality with the higher degree of fidelity;



the abstract – seeks to maintain a certain abstraction in the characterization of the digital model to allow understanding and evaluate certain formal relations between some elements of the design without the interference of the realistic persuasion [Fig. 2.16].

The CAVE is an example of an immersive virtual reality system, and consists in a cubic space

21

equipped with projectors and sensors. Using special glasses, the user movement interferes in the projected simulations.

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Figure 2.16 Programatic time flux studies modeled and rendered for the Nieuwegein Plan, designed by Ben van BerkeL.

In comparison with hand‐drawing and physical model representations, the digital model became a strong alternative for the visualization of three‐ dimensional qualities of the architectural design. In a book edited by Ojeda & Guerra (1999), big architectural firms like KPF, Rafael Viñoly, SOM or Cesar Pelli describe the importance of those digital simulation and communication possibilities in their work since the 80’s. Rejecting the exclusive utilization for the production of 2D drawings, computers became more integrated throughout the design process, assisting all drawing tasks associated with its study, description and presentation.

Cesar Pelli (Ojeda & Guerra, 1999: 44‐45) is clear about this fact when he explains that after an initial period where “the first use of computers was limited to the generation of production documents, like detailed plans, elevations, sections and repetitive drawing studies”, the emergence of advanced hardware and software made it possible the “study of more complex forms, which were difficult to be reproduced with paper and cardboard, because it turned faster the production and edition of distinct formal options before making more detailed physical models”, and allowed “designers to see realistic representations of the design in short­time periods, and directly in a CAD environment”22.

Besides their multiple visual possibilities, digital modeling processes had also some important operative limitations. During the 1980’s, software Translation from Spanish to Portuguese done by the author.

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possibilities to create designs directly in 3D were mainly resumed to a limited number of geometric primitives (i.e., box, sphere, cylinder, pyramid).

The alternative, which became the standard approach to 3D, was to take 2D information (i.e., lines, curves and shapes) as the basis for the generation of more elaborate 3D geometries. In this fashion, for instance, surfaces were derived from open lines, while solids were created out of closed lines through functions like extrusion, revolution or ruling. In both cases, 3D modeling represented a time‐consuming activity, and the possibilities to edit or transform those 3D entities were resumed to a basic set of operations like Boolean. This fact was decisive to discourage thinking and generating architectural designs in three‐dimensions with the computer. The bi‐ dimensional space inhabited by flat representations continued to be the territory where design thinking and decisions mostly occurred. Given that throughout the process any design change implied the correction of all affected 2D drawings, a digital 3D model produced at early stages could become quickly obsolete [Fig. 2.17]. In practical terms, this rigid condition tended to relegate the creation of 3D digital models for the final stages of the design process, where almost all variables were already clarified and described, and to serve mainly design presentation purposes23.

Figure 2.17 Conventional 3D digital modeling departs from 2D representations.

During the 90’s the CAD industry tried to overcome this problem by offering more flexible 3D

23

modeling options. ArchiCAD, which was launched by Graphisoft for Apple Macintosh in 1987 and for Windows in 1993 explored an object‐oriented technology seeking a seamless integration between 2D drafting and 3D modeling. Autodesk explored the integration of a direct link between two programs, AutoCAD (suited to drafting) and 3D Studio (suited for 3D modeling and animation), to encourage and facilitate the update of 3D models. However, this trend still meant a 2D approach to architectural design where 3D was a consequence and not its cause. Created by AutoDesSys, Form Z was another popular software launched in 1991 to offer advanced 3D modeling technology in a moment where design was ruled by 2D drawings.

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However, although reaching the three‐dimensional world, the use of such CAD software did not change at all the processes that mediate conception and construction in architecture. The computer is still understood as a representation machine where the 2D digital drawings tend to imitate drawings produced manually on the drawing‐board, while the 3D digital models tend to imitate physical models. Furthermore, the rigid digital modeling capabilities offered by the available CAD software, discourages any relevant conceptual digital approach. Thus, despite the higher sophistication introduced in the visualization of the design project, it can be argued that 3D digital representations followed similar ambitions and goals than the ones aimed by analogical representations throughout the last five centuries [Fig. 2.18]. Thus, both the conceptual and the constructability dimensions of the architectural design project still remain foreigner to the digital processes. For instance, the foundations of the architectural tendencies of those times, known as post‐modern movements, resulted from historical and philosophical discourses and motivations, rather than the use of a specific representation technology like the digital one.

Figure 2.18 Physical model of Corbusier’s Vila Savoye, for presentating the design idea.

2.3.3 Phase 3: Conception

It was only almost 30 years after the earliest applications of computers in architecture that other modes of using it started to be explored. The third phase was thus characterized by a deeper exploration of the computer to assist the architect in the conception of architectural projects [Fig. 2.19]. The

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roots of such thoughts can be found in the academic level during the 1970’s and 1980’s. Then, people like Stiny and Gips developed the shape grammar concept, questioning the lack of a philosophy in CAD applications to enhance design reasoning and creativity, and Mitchell et al. (1987) envisioned the use of computer programming to design custom CAD tools for architectural research and exploration.

COMPUTER

Figure 2.19 Phase 3: Conception.

Productivity

Visualization

Conception

(2d drafting)

(3d modeling)

(computation)

Following those precedents, one of the most clear epicenters of this critical spirit flourishing during the 90’s, took place inside the academic world, more precisely, at the Columbia University in New York. In 1988, Bernard Tschumi became dean of the Graduate School of Architecture, Planning and Preservation and started to investigate if “could a school, by definition an institution in which knowledge is transmitted, become a place for generating new forms of architectural thought” (Tschumi & Berman, 2003: introduction).

Understanding the increasing interference of digital technologies in the world24, Tschumi decided to foster a critical revision of the computers role in architecture. He did that by entrusting a group of young architects, more comfortable with the use of digital technologies, with the task of leading the most advanced design teaching classes in the school. Called as paperless studios, these classes promoted “an unprecedented integration of new computer tools into design studios, where digital technology was conceptualized as a mode of thinking about architecture rather than as a The influence of digital technology in contemporary culture became clear in the 80’s when

24

supported the consolidation of a society whose economic, political and cultural activities were increasingly less material‐based, and more based on information production, manipulation and transaction. During the 90’s, the development of global computer networks, like the Internet, also intensified the logics of virtualization behind this information society. “Life on Screen” by Sherry Turkle (1995) or “City of Bits” by William J. Mitchell (1996), or “The Rise of the Network Society” by Manuel Castells (1996) or “Cyberculture” by Pierre Lévy are four books that describe some relevant changes that were taking place at the level of the individual, the cities, the society and the culture in general, all promoted by the digital.

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simple drafting machine” (Tschumi & Berman, 2003: introduction) and were oriented by architects like Greg Lynn, Hani Rashid, Scott Marble, Stan Allen or Bill MacDonald.

As its own name suggest, the paperless studios encouraged the use of digital processes to assist the whole design development, challenging the traditional production of physical representations (Barhydt 2995). Recognizing that the lack of creativity in the use of CAD technologies should mean more than drafting and visualization, the architects leading those classes started to look into other disciplines to observe how their processes and products were being revolutionized by the use of computers. Dealing with intricate problems of geometric modeling and simulation, the software used in the cinema, automotive or aerospace industries presented particular design tools that suggested appealing opportunities for the conceptualization of architectural projects. Computers could thus assist in the generation of architectural forms – morphogenesis ‐ through an array of alternative design techniques.

For instance, the exploration of NURBS25 surface modeling capabilities, included in the programs used to design cars and airplanes, opened the possibility for investigating free‐form 3D shapes26, which would be very difficult to create and control by means of 2D representations, either analogical or digital. Also, belonging to software used for the creation of animations and special movie effects, digital techniques like Morphing27 and Particles Animation28 can assist the production of interactive design experiences based on dynamic and adjustable simulations. On this respect, Rashid comments his own experience about this kind of digitally enhanced creativity saying that he took “the notion of “paperless” very seriously in the sense of it being a complete, radical experiment – to actually rid ourselves of

NURB is the acronym of Non‐Uniform Rational Basis Spline, and consist in the mathematical

25

representation very helpful for the description of free form geometries.

Free‐form shapes can be considered a class of forms that are characterized by an irregular

26

geometry that is not conformed to conventional rules of composition. The complexity of a free‐ form shape, like a double curved surface, can only be captured by means of a three‐dimensional model. Thus, traditional systems of 2D representations are not sufficient to describe the whole geometric information contained in free‐form geometries.

Morphing is an animation technique that transforms an image into another in a continuous

27

changing effect.

The animation of particles systems is a digital technique that allows representing very

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complex and dynamic phenomenon like fire, smoke, wind, rain, water movement, etc.

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not the paper so much, but what the paper implies as an authority” (Tschumi & Berman, 2003: 24).

This academic paperless experience ended‐up influencing the world of architectural theory and practice of the 90’s, and contributed for a disciplinary turn into new aesthetic, formal, technological and cultural possibilities. Reacting to the formal language of Desconstructivism associated to Jacques Derrida philosophy, and to the historicist post‐modern semiotic, two complementary trends emerged in practice, in the beginning of the decade. On the one hand, at the formal level, there was an interest in the exploration of curved and organic shapes that defied the rules and limitations of Euclidian geometry. On the other hand, at the design foundation level, there was an interest in the use of philosophical concepts launched by Gilles Deleuze29, or scientific ones coming from the world of computer science and biology, drawn by auth3ors like D’Arcy Thompson, René Thorn, Benoît Mandelbrot or James Gleick30. Due to their particular nature, these practical and theoretical approaches may be related to the influence of the computer in practice.

One the central actors of this period, Greg Lynn edited in 1992 an issue of the Architectural Magazine (AD) entitled Folding in Architecture, which quickly became one of the most important publications capturing the spirit of those times. Inside, there are celebrated essays that point out to new design possibilities like “Architectural Curvilinearity. The Folded, the Pliant and the Supple”, written by himself, “Towards a New Architecture” by Jeffrey Kipnis,

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Presented in books like A Thousand Plateaus (1987), The Fold: Leibniz and the Baroque

(1992), Difference and Repetition (1995) or What is Philosophy? (1996) are some of the most influential books written by the French philosopher Gilles Deleuze. In these works, he launched books that influenced the world of architectural production in the 90’s like: “the fold”, “abstract machines”, “virtual / actual” or “body without organs”. In the architectural practice, Peter Eisenman, Bernard Cache or Greg Lynn are some of the architects that most explored the practical implications of such concepts, while Brian Massumi or Manuel de Landa are some of the theoreticians that most elaborated architectural thoughts in their books from Gilles Deleuze philosophy. One of the most direct correspondences between Deleuze’s philosophy and architectural practice can be found in Bernard Cache’s book “Earth Moves”, from 1995.

Some relevant references in the field of Science and Biology that influenced architectural

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design thinking were: D’Arcy Thompson with his topological studies of biological forms described in his book “On Growth and Form” (1917); René Thorn and the catastrophe theory drawn from his mathematical work on the 1960’s; Benoît Mandelbrot and his studies on Fractal Geometry published in books like “The Fractal Geometry of Nature” (1982); James Gleick and his Chaos Theory presented in his book “Chaos: Making a New Science” (1987).

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or the transcription of “The Fold – Leibniz and the Baroque”, one of the seminal texts written by the French philosopher Gilles Deleuze.

The intensive search for alternative design approaches with the computer, mostly performed by young architectural practices, gave origin to the expression digital architecture. As defined by Kolarevic (2000) in a paper with the same name, this concept encompasses a wide range of digital morphogenetic processes31. In this context, architects like Greg Lynn or Lars Spuybroek (NOX) programmed animation techniques to produce interactive digital formal set‐ups to inform the generation of designs [Fig. 2.20]. At the same time, pioneering the application of parametric design techniques in architecture, Bernard Cache and Mark Burry started using mechanical engineering software to conceive and control forms by exploring geometric variation possibilities [Fig. 2.21]. But the programmable and interactive environment of the digital medium also encouraged more radical approaches. Assymptote architects proposed virtual architecture projects for the Guggenheim and the New York Stock Exchange, Karl Chu investigated evolutionary rule‐based processes to sustain a kind of a genetic approach to architectural design, and Marcos Novak programmed interactive environments in the digital realm, suggesting digital environments as legitimate territories for architectural intervention [Fig. 2.22].

Many other relevant works of this period were developed by other architects like Mark Goulthorpe / dECOi, Kas Oosterhuis, Reiser + Umemoto or Stephen Perrella. Edited in 1998, Peter Zelnner’s book “Hybrid Space” is a good reference about many of this projects and the vibrant creative spirit behind their formulation.

Branko Kolarevic (2000) explained that “digital architecture” refers to “computationally

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based processes of form origination and transformation”. On the contrary of what could be understood in a first glance, this concept is defined by the medium and tools used by architects to conceive their projects, and not by an eventual (im)material condition of architecture.

Kolarevic organizes these approaches in computational concepts like: “topological space (topological architectures), isomorphic surfaces (isomorphic architectures), motion kinematics and dynamics (animate architectures), keyshape animation (metamorphic architectures), parametric design (parametric architectures), and genetic algorithms (evolutionary architectures)”.

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Figure 2.20 Greg Lynn’s design for the Port Authority Gateway in New York (left). The Beachness, project for Noordwijk, by Lars Spuybroek / NOX (right).

Figure 2.21 The use of parametric design software by Bernard Cache (left) and in the Sagrada Familia extension works under the orientation of Mark Burry (right).

Figure 2.22 The Virtual Guggenheim design by Asymptote (left). and the Paracube project by Marcos Novak (right).

In all these computer‐based approaches, design conception occurred by means of interactive, topological, generative and evolutionary processes, which could not be supported by means of traditional analogical tools. Thus, unlike in the previous phases, these digital approaches fostered alternative formal strategies that would impact architectural discourse and production during the decade.

Launched by Greg Lynn in 1995, the “Blob” 32 concept is a clear example. It represented an emergent paradigm of formal complexity associated to curved geometries, topologically variable and with multiple possibilities of This concept was presented by Greg Lynn in the article “Blob”, which was published for the

32

first time in Journal of Philosophy and the Visual Arts in 1995, and then reproduced in Lynn, 1998. According to Lynn, the blob is: “a class of topologcal geometric types for modeling complex aggregates that exhibitis the qualities of multiplicity and singularity outlined above has recently been developed. The most interesting example of these topological types are isomorphic polysurfaces or what in the special effects and animation industry are referred to as meta­clay, meta­ball or blob models. The explantion of the organization of these topological geometries actually outlines a working schema for a new typology for complexity”.

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aggregation and combination. At the same time, the world of publications devoted to the use of computers in architecture left to be mainly dedicated to describe the foundations behind computer graphics and geometric representation, to start capturing and illustrating an higher impact, recognizable at the production level. Besides the publications already mentioned, the series of books of the IT Revolution in Architecture series edited by Antonino Saggio and several issues of the Architectural Design magazine edited during the 1990’s, clearly demonstrate the interference of computer going beyond drafting productivity and visualization purposes to affect the level of architectural production.

In all the genuine digital design approaches described before, the computer’s calculation power, clearly superior to any other tool or human mind, converges with the sophisticated representation possibilities in the screen.

The computer ceased to be understood solely as a machine for representation, which does not interfere in design conception, to start being a machine for (information and geometric) computation. In this sense, it really establishes a partnership with the architect to support the development of architectural designs in novel ways, revealing its potential facing traditional analogical tools and processes. The work developed by Duarte (2001) about customizing mass housing, demonstrates how such digital approach to conception can expand the world of design possibilities. Based on Siza’s Malagueira Houses, his research proposed a digital design system that could generate an infinite number of new versions while respecting Siza’s design principles and intentions. Such interactive approach, base on computation, recalls Pimenta (1991: preface) who sharply acknowledges this novelty by detecting that “for the first time architectural drawing isn’t only a frozen moment of a process of movement”.

In the most genuine techniques of the digital medium, like in parametric modeling or computer programming, the architect observes the automatic calculation and representation of solutions in real‐time, which emerge out of a previously defined set of design rules. In those approaches, as Gernot Bauer refers to, “the architects finds himself –as a designer­ controlling a process rather than a design” (Rocker, 2002: 17). Instead of designing a particular shape, he designs the conditions for the emergence of form(s). Also, the direct manipulation of geometries on the screen, which can resemble the hand‐drawing experience in a piece of paper, is replaced with the indirect

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intervention through the edition of its mathematical description. As a result, the design form becomes a computed entity rather than a drawn one, which can open new design avenues.

However, despite the experience of an unprecedented design freedom, the possibility of geometric computation also originates negative and recurrent reactions coming from many theoreticians and professionals, like: 

the idea that computers could have an active role in the design conception, through generative and automated representational techniques, raise a polemic debate both around the design’s authorship (the man or the machine) and the possibility that architects would lose control over the project. The fear of a new “mechanization” emerges, where the designer’s critical thought could be subjugated by productivity‐oriented desires driven by technology, in other words, where art seems to vanish in favor of science.



the possibility to design any imaginable geometry in the screen is so fascinate that architects seem to develop the formal aspects of the design totally independently of its inherent constructability. The fact that many of the most celebrated architects in this period, like those presented in this text, didn’t get to build their projects, encouraged many critiques that pointed the computer as a tool that was just promoting a depreciated kind of new beaux­arts.



despite the digital technique used, the visible obsession about curved geometries is realized by many as an stylistic option almost imposed by technology which disturbs the architect’s critical autonomy. The specificity of the design solutions have been traditionally dependent on factors like context, history, materials or economy and they seem to be frequently ignored in favor of a stylistic trend that directly expresses the possibilities of the technology.

By reflecting on this context, it is not difficult to agree that most of the creative approaches influenced by the computer possibilities during the 1990’s seem to fall down in an excessive formalism with no correspondent physical translation. While aesthetics and complexity seemed to be the unique parameters that judge their relevance, those proposals exposed a clear gap between design and construction, which drew a widely discussed opposition between the digital and the material. Lacking a certain credibility raised by constructability issues, as noted by Kolarevic (2001), these more

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radical experiences have to be credited by their positive contribution to unveil the potential of computers to affect the design practice. By pushing forward the disciplinary knowledge and assimilation of digital processes, they also stimulated the collective imagination around architectural design.

One could thus argue that the unbuilt digital architectures of the early 90’s could be inscribed in a long time tradition of paper or talking architecture33, where we can find acclaimed works done by authors like Giovanni Battista Piranesi (1720–1778), Étienne‐Louis Boullée (1728–1799), Constant Nieuwenhuys (1920–2005), the British team Archigram (1960’s) or the Italian group Superstudio (1960’s) [Fig. 2.23].

Figure 2.23 Unbuilt paper architecture: analogical vs. digital architecture: the imaginery prisons drawing by Piranesi (left). Peter Esenman’s Virtual House project (right).

2.3.4 Phase 4: Construction

Finally, the fourth phase in the integration of digital technologies in architecture has consisted in the possibility of the computer to influence the realm of construction, by supporting a direct connection between digital and material information. Early implementations in practice can be traced back to the beginning of the 1990’s, but its wider assimilation became a true reality during the present century [Fig. 2.24].

Paper or talking architectures are some of the names used to classify certain architectural

33

proposals that never reached the built form but, nonetheless, have played an important role in the history of the discipline. These proposals can embody different aspirations, balancing between idealistic design manifestoes or more realistic proposals that failed due to some processual reasons. For instance, looking into recent architecture, one can identify early Zaha Hadid proposals represented in her impressive paintings as an example of the former case, while Daniel Liebskind’s design for the Victorial Albert Museum can be associated with the latter case.

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COMPUTER

Figure 2.24 Phase 4: Construction.

Productivity

Visualization

(2d drafting)

(3d modeling)

Conception

Construction

(computation)

(engineering + manufacturing)

As discussed before, the technical capability to digitally represent any imaginable geometry made evident the lack of practical means to deal rigorously and economically with the construction of the most complex ones.

For instance, although it can be easily represented on the screen, the consideration in architectural design of a double curved shape challenges its engineering and construction, raising questions such as the following ones: 

How to describe its irregularity through the conventional system of orthographic representations that reduce three‐ dimensionality to a finite set of bi‐dimensional drawings?



How to analyze the specific engineering phenomena that occur in it, by means of traditional calculation methodologies?



How to assure precision, fastness and economy in manufacturing while being limited to the common manual and mechanical fabrication processes?



Transgressing standardization logics, how to produce in a feasible way a set of differentiated building components that are usually required to solve the construction of a complex shape?

Once again, the solutions to overcome all these challenges were born outside the field of architecture. It was in the field of mechanical engineering, close to the aeronautic and automotive industries, that, mainly under military influence, Computer Aided Engineering (CAE)34 and Computer Aided Manufacturing (CAM)35 technologies started to be developed by the end of the 1950’s. Taking advantage of the digital media, both technologies evolved simultaneously with the CAD ones. Using the digital drawings and models CAE technologies are presented and discussed in detail in the 3.2.2 of this thesis.

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CAM technologies are presented and discussed in detail in the 3.2.3 of this thesis.

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CAE allows the development of engineering analysis in the computer avoiding physical testing, while CAM allows the direct control of physical manufacturing processes, involving Rapid Prototyping / Manufacturing (RP/RM)36, Computer Numerically Controlled (CNC)37 fabrication or robotic technologies. From conception to final production, the integrated use of CAD/CAE/CAM processes allowed interdisciplinary teams to go through the full cycle required to produce an object using the digital medium. Working with comprehensive 3D models in the computer, virtual prototyping techniques became a viable alternative to the production of time‐consuming and expensive physical tests and prototypes.

One of the most celebrated stories about this trend was played by Boeing in the production of its 777 aircraft38. Although Boeing had used CAD/CAM systems before, it was in the end of the 1980’s that Phil Condit, the general manager for this project, “made the decision to fully adopt digital technology (…) as something that would be integral to inaugurating an entirely new approach to aircraft design” (Yenne, 2002: 36). To support this initiative, Boeing invested in the integration of CAD/CAM technologies based on Catia39 software whose three‐dimensional capabilities avoided the necessity for physical construction of mock‐ups and prototypes40. Although this virtual prototyping approach was already successfully implemented within the automotive industry, by firms like Daimler Benz, BMW, Fiat, Volvo and Saab, “no project as large as a jetliner had ever been designed without a full­scale mockup” (Yennes, 2002: 36). Dealing with a very complex object, this RP /RM technologies are part of what is called Additive Fabrication processes, which are

36

presented and discussed in detail in the 3.3.1 of this thesis.

CNC fabrication technologies are presented and discussed in detail in the 3.2.2 of this thesis.

37

To see a complete overview about this story, see: Yenne, B. (2002): Inside Boeing: Building the

38

777, MBI Publishing, St Paul, MN. CATIA (Computer‐Aided Three‐dimensional Interactive Application) is considered one of the

39

most advanced CAD/CAE/CAM software today. It was created by the end of the 70’s by the French company Dassault Systems, and among its users are important companies like BMW, Mercedes, Honda, Boeing or Airbus.

In the 2000 “New Technologies in Architecture” Symposium held at Harvard University,

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Robert M. Abarbanel from Boeing Company, explained that in the end of the 1980’s “the forward thinking leaders at Boeing chose to design that airplane without the traditional class 3 physical mock­ups that made the design, planning and manufacturing so expensive. They chose , instead to use 100% electronic mock­up with the computer aided design (CAD) being done on Dassault Systemes’ CATIA product” (Bechthold et al., 2000: 1). Consisting in complex assemblies of multiple parts, with different shapes and materials, aircraft design and production processes becomes thus particular interesting for architecture. This Boeing’s presentation in an architecture symposium demonstrates the particular attention that architects are paying nowadays to the possibility for innovation emerging out of technology transference processes.

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strategy demonstrated clear benefits in terms of the achieved precision, flexibility, time and economy, which made the Boeing 777 the world’s first all­ digital aircraft (Yennes, 2002: 36)41. Besides aeronautics and automotive industries, this promising paperless approach to production has been implemented and revolutionized a growing number of disciplines and industries, like ship‐building, product design, textiles, medicine and, necessarily, architecture42.

In architecture, due to the sculptural nature of his work, Frank Gehry was one of the architects that felt the necessity to urgently find answers for the questions launched in the beginning of this sub‐chapter. The story behind his Walt Disney Concert Hall project clearly illustrates this. As Friedman explains (2002: 15), “because Gehry’s 1988 design for the Hall was complex and not thoroughly understood by the executive architect, the estimates generated from their work were astronomical and the project came to a grinding halt”.

Conventional representation methods, based in physical models and manual drawings, were not sufficiently effective to describe and communicate the Intricacy of the proposal to the external specialists. This incident fostered radical changes in the organization of the office. In this restructuration, James Glymph, an executive specialist, was hired with the mission of improving the in‐house technical expertise to assure the full control of the projects, from conception to construction. To achieve this, Glymph investigated how the aeronautic industry was successfully employing CAD/CAM technologies for the production of complex shapes and assemblies. It became then clear that the answer for Gehry’s longing was depending on the adoption of similar methodologies, which also suggested the possibility of expanding Gehry’s formal language into territories of increase freedom and complexity.

During this research, I had the opportunity for visiting the Boeing factory in Seattle, where

41

the company produce the 747, 767, 777 models and, more recently, the 787 Dreamliner. In the tour, it was possible to observe the use of computer technology in many different ways, assuring the production of such a complex object. One of the most impressive aspects was the realization of the distributed collaborative production throughout the world of the different parts, that came together in the factory, configuring an incredible coordinated and precise process.

Just to give an example about how architecture was late in the assimilation of new CAD/CAM

42

technologies, during this dissertation I came across a very interesting book from 1991 called CAD/CAM in Restorative Dentistry: The Cerec Method, written by N. Jedynakiewicz and N. Martin (Liverpool University Press). Before architects use these technologies in building construction, engineers were employing them to create big products ‐ aircrafts ‐ and medicine was using them to produce very small elements – dental prosthesis.

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Built in 1992 in less than a year, the curved geometry of the Fish Sculpture in Barcelona was the first test of the use of CAD/CAM processes in practice (Lindsey, 2001) [Fig. 2.25]. To overcome some imprecision inherent to the geometric descriptions of the general CAD software used in architecture, the office integrated the CATIA software, a well‐established software in the aeronautic and automotive industry that allowed for the production of digital models sufficiently accurate for enabling the performance of digital analyses

Figure 2.25 Fish sculpture in Barcelona.

and fabrication processes43. The success of this work encouraged Gehry to continue throughout his work the exploration of CAD/CAM technologies for the inventive production of building components with different materials and customized geometries. The radically innovative potential of the computer became definitely demonstrated when it supported the successful conclusion of the Walt Disney Concert Hall in 2003, almost fifteen years after the failure of his first proposal [Fig. 2.26].

Figure 2.26 Walt Disney Concert Hall in Los Angeles (CA, USA) after its completion.

By establishing a direct connection between digital and material information, the integration of CAD/CAM technologies in architecture is specially promising at the level of: 

precision – by radically incrementing accuracy in the manufacturing processes;



geometric freedom – by expanding the possibilities of making forms and shapes with greater complexity;



variability – by turning affordable the serial production of elements based on differentiation, instead of repetition;

Some of these accuracy problems are discussed in 3.2.1 of this thesis.

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However, the implementation of CAD/CAM technologies in practice does not imply by itself an innovative approach or result. Once again, the interest on these technologies can balance between two tendencies: 

the search for higher efficiency in the production processes, looking for economic, time and precision benefits;



the search for new architectural opportunities derived from a critical awareness regarding the singular potential of digital technologies;

In the first tendency, for architects using computers to carry out non‐ creative tasks (i.e., drafting, documentation, visualization), CAD/CAM processes can be appealing to make more expedite and rigorous the physical execution of their designs. However, the formal and material nature of those projects still embodies the possibility of being accomplished by traditional means. For instance, many of the large architectural firms with great resources tend to embrace these technologies to increment their productivity gains.

A similar interest can be found in the reconstruction and extension works at the Sagrada Familia in Barcelona44. Since the 1990’s, CNC fabrication and Rapid Prototyping processes have been used to accelerate and improve the control over the building process [Fig. 2.27]. Indeed, the geometry of the new additions to the Temple was devised from the existent parts designed

by Gaudi, who, despite their apparent complexity, conceived and ruled them in a way to facilitate their physical production by craftsmen. However, the benefits in terms of speed and precision achieved with the implementation of CAD/CAM processes, sometimes successfully combined with craftwork, has brought clear benefits for the evolution of that work.

Looking for understanding and respecting Gaudi’s tradition, the extension works of the

44

Temple can be considered as following such tendency in using digital technologies in general terms. In fact creative endeavors digitally motivated can also be distinguished. In recent years, for instance, the use of generative design techniques have been employed for conceiving some parts of the building.

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Figure 2.27 The use of digital technologies in the extension works of the Sagrada Familia temple, in Barcelona.

In the second tendency, architects envisioned the potential of CAD/CAM processes to foster innovative formal and material approaches.

Understanding a mutual influence between design and construction, their digital design explorations integrate material considerations to inform the formal conception of architectural projects. When investigating unusual forms and material strategies, these practices take advantage of digital processes to go beyond the traditional making of physical models. The digital production of physical mock‐ups, which reach the 1:1 scale, or prototypes, which test final building materials, become part of the design process45.

This interest guided the work of several architects like Bernard Cache, Bill Massie, Greg Lynn, SHoP, Bernard Franken, Kaas Oosterhuis or François Roche. Some of them were presented in the book Digital Real: Blobmeister, First Realized Projects. Realizing that after “a few young and innovative architecture firms have seized the opportunity to explore the limits of digital potentials”, the editor argued that “the time has come to present the first built examples [which help] to refute the prejudice that cyber artists are unrealistic This distinction between mock‐ups and prototypes is based in Kalay’s description.

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dreamers” (Schmal, 2001: 7). Works like the BMW Bubble and the Web of North Holland pavilions, respectively designed by Bernard Franken (1999) and Kaas Oosterhuis (2002), exhibit a formal and building consistency that are exemplar of the conceptual and material opportunities emerging from integrated digital design and manufacturing strategies [Fig. 2.28].

Figure 2.28 BMW Bubble pavilion designed by Bernard Franken (top). Web of North Holland pavilion designed by Kaas Oosterhuis (down). Curved freeform shape and variable building components are common features in both buildings.

But these design opportunities conceived from early material considerations do not end up with just exploring the new fabrication possibilities. Sharing the same digital models, the use of CAE technologies by engineers can introduce a creative input in the process. On pair with the traditional search for efficient building engineering solutions, the friendly graphic representations of the building behavior produced with these digital analysis can suggest creative opportunities that otherwise would never be considered. For instance, the final shape of many of Norman Foster’s buildings results from early considerations of engineering strategies. The overall design of the debating chamber of the City Hall building in London, with its impressive spiraling ramp, was devised from a digital integrated process where design intentions were tied to acoustical analysis [Fig. 2.29].

In different way, the Catalan architect, Josep Lluis Mateo, when designing a

Figure 2.29

tower for a competition, decided the openings on its facade with the

chamber room, designed by

visualization of a CAE representation. Realizing the inefficiency of the

City Hall building and its Norman Foster.

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structural behavior of the building’s irregular shape through the finite element analysis representation, Mateo envisioned the opportunity to develop variable openings in the facade [Fig. 2.30]. Instead of working on finding an efficient engineering solution for a previously conceived facade design, the architect decided to adapt the shape of the openings to improve the structural performance of global form of the building. Although the final effect could be easily understood as an aesthetic‐driven intention, it cannot be detached from the integrated CAD/CAE/CAM experience.

Amid these two positions there are, naturally, intermediary approaches

Figure 2.30

where many of Frank Gehry’s works could be included. As his creative

Josep Lluis Mateo proposal

approach is essentially analogical, through sketches and physical models,

Maag Areal Company. The

the use of CAD/CAM technologies initially emerged in the office to permit the physical translation of his ideas. Although the materials employed in his models immediately suggest the construction logics of the design46, the complexity inherent to the geometric arrangements he usually explores would be hardly controlled and executed with traditional processes, as the Walt Disney Concert Hall project experience had demonstrated. Thus, slightly different from the first case scenario, the use of computer in the majority of Gehry’s practice is still critically relevant because it enables the translation of the architect’s ideas into built form, even if they are not digitally generated. The design and construction of the Zoolhof complex in Dusseldorf clearly demonstrates this approach [Fig. 2.31]

46

More information about the nature of Frank Gehry’s process can be read in a text written by

the author called “Liberdade Calculada: O Processo de Frank Gehry”, which was published in in the Portuguese magazine Arquitectura e Vida n. 66 (pp. 36‐40), in 2005. This text was developed with the help of Dennis Shelden, director of Gehry Technologies, and after the author’s visit to Frank Gehry’s office and buildings in Los Angeles, in 2005.

for the Office Tower of the CAE diagrams of structural analysis (left) stimulated the design of variable openings in the building facade (center and right).

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Figure 2.31 The use of CAD/CAM technologies in the Zoolhoff Complex in Dusseldorf, for fabricating customized formwork. From physical models, to digital design and manufacturing, to the final building.

Previously viewed as problematic, the computer offers now solutions for the physical translation of designs it helps to conceive. CAD/CAM processes have thus the potential for conciliating digital technology with those with a negative opinion about the use of computers in practice. Spreading the perception that “design vocabularies can be expanded and that same designs can be made with a quality and precision previously difficult to achieve“ (Schodeck, et al., 2005), the general interest about CAD/CAM technologies grew and spread quickly. Since 2000, many authors have edited detailed publications about this theme, like Callicot (2001), Bechthold (et al., 2000 e 2003), Kolarevic (2003 e 2005), Chaszar (2006) or Schodeck (et al., 2004), just to name a few, while influent magazines like the Architectural Design, dedicated special numbers to the subject. Simultaneously, CAD/CAM technologies became one of the most present and discussed themes in scientific meetings and academic symposiums47, and a growing concern in the architecture curriculums in the schools worldwide48.

This fact can be easily verified In the last years by consulting the agendas of the yearly

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conferences promoted by the Association for Computer Aided Design in Architecture (ACADIA), the Association for Computer Aided Architectural Design Research in Asia (CAADRIA) or the association for Education and Research in Computer Aided Architectural Design in Europe (eCAADe), or the academic symposiums that took place in several architecture schools, like those at UPenn, Yale U., Harvard GSD or TU Delft.

This can be verified by consulting the undergraduate curriculums and post‐graduate programs

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offered in schools like Columbia U., MIT, Harvard GSD, UCLA in USA, ETHZ in Switzerland, ESARQ‐ UIC and IAAC in Spain, TU Delft in the Netherlands, or the AA and Bartlett in UK.

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2.3.5 The rise of computer networks

In parallel with the development of computer‐based architectural processes described before, the reference to another digital development should be added into the discussion49: the rise of computer networks. Mainly flourishing during the 1990’s, the possibility to connect computers in local networks (i.e., at the office) and in global networks (i.e., the internet) has challenged the nature of communication in every human activity. With the widespread digitalization processes, almost any type of information can be converted into the digital format, which enables its instant transmission through computer networks to any part of the world, at any time [Fig. 2.32].

Considering existing physical transportation systems (e.g., aerial, nautical

Figure 2.32

and by ground) and analogical communication technologies (e.g., telephone,

Map of the Internet showing

fax), the introduction of digital networks have dramatically improved current

internet users by country in

the worlds distribution of

possibilities and opened new alternatives by blurring traditional space and

2007, according to the

time constraints. For instance, in architectural practice, e‐mailing digital files

became an alternative for the delivery of printed documents and, more As explained in the end of the introduction, the present chapter is dedicated to understand

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how digital technologies can expand design and building possibilities in architecture, by affecting the nature of representation tools and construction processes. In this context, the advent of computer networks was not included in the historical perspective because it doesn’t influence directly the architectural possibilities that were analyzed. However, indirectly, its impact cannot be underestimated because of the collaborations it can foster, which otherwise would be hardly achieved. For instance, creative specialists and efficient building companies from different parts of the world can now be grouped around a project through the internet, thus increasing the conditions for the emergence of visible innovation in the architectural solutions. With traditional communication systems, those teams could never be sustained and the consequent productive results could never be achieved.

Internet World Stats.

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recently, of physical elements too50. At the same time, architects can avoid its physical presence in distant places by means of online video‐conferences.

At another level, recent CAD software capabilities explore computer network facilities to allow different people, within the office space or distributed throughout the world, to work concurrently in the same files. In this context, digital networks can support the deterritorialization of the working environment, giving shape to the idea of the virtual design studios that were very much discussed during the 1990’s.

The possibility for distant communication has supported the radical expansion of the geographic scope of architect’s intervention to a degree never seen before. Today, both big firms and small studios have the means to manage working simultaneously in distant places of the world. For instance, Zaha Hadid, Frank Gehry, Norman Foster or Herzog & de Meuron are running big commissions in Europe, America, Asia and Middle East at the same time, which would be hardly conceivable in a recent past. Although it is possible to identify new communication opportunities and recognize emergent methodological changes, it is not very clear that computer networks can produce a direct impact in the architectural design and construction possibilities. However, some indirect interference can be acknowledged due to the singular quality of the collaborative relationships it can foster.

Considering the world as the search space, architects can think organizing interdisciplinary teams and orchestrate the building production processes based on expertise and efficiency goals rather than geographic proximity or time synchrony factors. By approximating talented people that otherwise could not be involved collaboratively, it is possible to argue that global computer networks can thus have an indirect influence on the quality of building production. In this context, the benefits of digital computer networks for architectural practice are making architects more and more dependent of computers today.

This tendency has been known as Personal Fabrication.

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THE DIGITAL IMPACT ON MATERIALITY

With the advent of digital design, engineering and manufacturing technologies, the relation between the information and physical worlds have been redefined. Overcoming the boundaries of CAD, architects are no longer simply concerned with conceiving elegant form in the computer, but with incorporating in their digital design processes, material properties and constructive strategies. The development of CAD/CAE/CAM processes have opened up the opportunity for developing architectural projects through cyclical incursions between digital information and material fabrication. By exploring such interaction, designers become more aware of the physical constraints of their proposals, but also, more vulnerable to the invaluable stimulus and motivations suggested by the material reality51.

A look into contemporary architecture reveals that many of current built works that are critically relevant today result from a deep involvement with material questions supported by digital technologies. Around the world, an increasing number of projects designed by larges practices (e.g., FrankGehry, Zaha Hadid, Herzog & de Meuron) but also by small studios and young individuals (e.g., Andrew Kudless or Chris Bosse), demonstrate a global tendency towards the exploration of an unprecedented geometric freedom, exercised at both the conceptual and material levels.

Such fact is at the basis of the emergence of some architectural interests, like:



complex forms and structures: the design of architectural forms and constructive solutions that are curved or irregular in their geometric nature52 [Fig. 2.33];

Following the tradition of architects interested in the link between ideas and matter, like

51

Antoni Gaudi, Buckminster Fuller or Frei Otto, there have been relevant works trying to develop computational systems capable of inducing the digital generation of form based in material definitions. Both obeying to optimization goals, the EifForm program centered in the automatic generation of non‐standard geodesic structures developed by Shea (1997), and the interactive computer application for the generation of centenary‐based structural systems developed by Killian (2006) are some relevant examples that blurs the conventional separation between design and engineering, digital and material and ultimately, arts and science.

Pottman et al. (2007) provides a concise study about the geometries that are employed in

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architecture, explaining the influence of digital technologies to enhnce the exploration of the most complex ones.

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

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mass‐customization design and production logics: the integration of variation and adaptation as a condition for both the generation of design solutions and building components [Fig. 2.34];



ornamental strategies: the exploration of innovative material effects resulting from design and fabrication possibilities in building surfaces or elements [Fig. 2.35];



material and building performance: the search for advanced behavior in buildings, for instance, by integrating interactive electronic systems, or implementing design and material solutions to enhance the sustainability of the built form [Fig. 2.36].

Figure 2.33 Complex shape of Peter Cook and Colin Fournier’s Kunsthaus in Graz; Complex Structure of the Herzog & de Meuron’s Olympic Staidum in Beijing.

Figure 2.34 Customizing mass housing work by J. P. Duarte, based on Siza’s Malagueira project (left). Mass production of customized metal panels in Frank Gehry’s Experience Music Project (right).

Figure 2.35 Surface as ornament in Klein Dytham’s Leaf Chapel (left).

Structure as ornament in Toyo Ito’s Serpentine Pavilion (right).

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Figure 2.36 Interactive interior space in NOX’s water pavilion in the Netherlands (left). Sound reactive structure designed

by Mark Goulthorpe / dECOi (right).

In this scenario of non‐standard architectural production53, unique building designs tend to require singular constructive solutions. In pair with the growth of such disciplinary interests, the building materials industry faces thus new production challenges to match them. Defying the limits of standardization, material innovation for contemporary architecture have emerged from two routes: 

the invention of new materials



the innovation in traditional existing materials.

Regarding the first one, recent developments in material science are leading to the emergence of new materials that can be “designed”, for instance, at a molecular level in a laboratory, to accomplish specific objectives and solve particular problems. A concise overview and analysis of this approach can be found in Addington & Schodeck (2005), Fernandez (2006), and Ritter (2007), where several material and technological developments are presented and classified. Facing those new opportunities, one can envision that part of current architectural questions dealing with manufacturing and performative aspects could be solved with advanced products developed by advanced engineering sciences, which Toshiko Mori (2002) calls “ultramaterials”. Also, at the performance level, the increasing exploration of electronics has proved to be a viable and powerful way for embedding smart and intelligent behaviors in materiality. This new kind of materiality has been employed in an increasing number of buildings, despite its difficult commercial diffusion. In the Vila Nurbs house, Enric Ruiz‐Geli (Cloud9) has

53

The emergence of a non-standard architectural production in the recent years gave origin to the exhibition “Non Standard Architectures”, hosted by the Center Pompidou in Paris, and curated by Frederic Migayrou in 2003. Besides the catalogue of this exhibition, this theme was also approached on an essay called “Towards a Non Standard Mode of Production”, written by Bernard Cache and Patrik Beaucé (2007) in 2003. Carpo (2008) also wrote about of this tendency.

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explored several new materials, like fabrics, ETFE or translucent concrete.

With its complex shape and structure, produced with the help of CAD/CAM technologies, this project is a true laboratory about the present and future of architecture materiality [Fig. 2.37].

Figure 2.37 Vila Nurbs under construction in Ampuria Brava in 2006 (top). The ETFE roof system (bottom left) and the integration of translucent concrete with a light system, in a concrete stairs.

In opposition to the new materials approach described above, rethinking the application of traditional materials in architecture through the use of digital technologies has been the other tendency in material innovation nowadays54. Through the use of CAD/CAM technologies, both architects and industrial manufacturers have means to define the fabrication processes of their constructive solutions and products in an flexible and individualized way. Questioning the limited way in which traditional building materials are currently available in the market, this tendency have unveiled new 2D shape, surface texture and 3D form opportunities. The exploration of these possibilities can occur in two ways. On the one hand, digital manufacturing technologies can be directly employed over materials like wood, stone or metals, for cutting and milling them in novel ways. On the other hand, they can be used in the innovation of formwork and molds to indirectly affect the Traditional materials are understood as existing materials that are easily available in the

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market (e.g., ceramics, concrete, glass metals, wood).

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production of materials like concrete and glass. In any case, new technologies have been used in old materials to rethink their applications facing current architectural interests described before [Fig. 2.38].

CONCRETE

STONE

WOOD

METAL

BRICK

CAD/CAM Technologies

Complex Geometries | Mass-Customization | Ornamentation | Performance

The realization of both tendencies and approaches, reveals a dynamic that has been conciliating more traditional views on the nature of the discipline,

Figure 2.38 Diagram showing how traditional materials have

linked to materiality, with more progressive ones, emerging from the use of

known innovative

advanced digital technologies.

applications in architecture

technologies. Projects

through the use of CAD/CAM

featured: pre‐fabricated

Complex by Frank Gehry

facade parts for the Zoolhof (concrete), pieces for the Diana Memorial by Gustafson Porter (stone), panel by

Bernard Cache (wood), panels

in the Walk Art Center by

bricks in installation for the

Herzog & de Meuron (metal),

2008 Venice Architecture

Kohler (brick).

Biennale by Gramazio &

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CONCLUSION

Referring to the historical overview presented in this chapter, it was reached a moment, in the beginning of this century, where the computer can interfere in any moment of the architectural process by offering true alternatives for analogical tools to fulfill any design interest [Fig. 2.39].

COMPUTER

Figure 2.39

Computer’s potential interference in the

Productivity

Visualization

Conception

Construction

architectural process today.

(2d drafting)

(3d modeling)

(computation)

(engineering + manufacturing)

Besides raising working efficiency and productivity, the use of CAD/CAE/CAM technologies can foster innovative design, engineering and fabrication avenues. With actual CAD tools, architects can digitally represent any imaginable form with absolute precision and control. Complementary, forgetting economic constraints for the moment, CAE and CAM technologies allow the development of engineering and manufacturing strategies towards the materialization of those shapes independently of its intricacy.

Thus, recalling Mitchell’s initial sentence that “architects tend to draw what they can build, and build what they can draw” (2001: 353), it can be concluded that, today, the extensive use of computers in practice has inscribed the architect within an expanded creative space of formal and material possibilities. In an exceptional way in history, a single technology has been directly producing substantial changes in both design and construction territories.

The following picture [Fig. 2.40] resumes the expansion of the opportunities emerging from the extension of the architect’s activity, again, into the moment of construction. The most evident one is the possibility to explore a new paradigm of industrial production in building construction – the mass customization – which, as Joseph Pine explains, represents a synthesis of the two long‐competing production systems, Craft and Mass production. In his words (1993: 50‐52):

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“Mass Customization (…) contains elements of both Craft and Mass Production. As with Craft Production, Mass­Customization commonly has a high degree of flexibility in its processes; it uses general­purpose tools and machines as well as the skills of its workers; it builds to order rather than to plan; and it results in high levels of variety and customization in its products and services. Moreover, like Mass Production, Mass Customization generally produces in high volume, has low unit costs, and often (but not always) relies on high degrees of automation.”

Renaissance

Industrial Era

Digital Era

Architect’s activity Representation Construction Modes of production Craft Production Mass production Mass Customization

Figure 2.40

Architect’s activity vs. production possibilities.

This same observation is applied in architecture by Peter Zelnner (1999: 13), who highlights that: can now commingle in CAD/CAM mode of creation, which can series­manufactured,

mathematically

coherent

but

differentiated objects, as well as elaborate, precise and relatively cheap one­off components”.

However, it should be highlighted that while revealing new avenues, the use of digital tools can also contribute to foster innovation in existing design and construction strategies. Frank Gehry’s practice, exemplary mastering traditional conceptual processes and advanced digital design processes, or the works at the Sagrada Familia, combining the advantages of digital fabrication technologies with the singularity of craftsmen production, are two examples that demonstrate the richness of the computer’s contribution for architectural practice.

“the unique character of handwork and systemic mass production produce

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Although the majority of architectural offices is still fixed to productivity and visualization goals, the innovative evidence of the most progressive practices seems to confirm the initial hypothesis that, after the Renaissance and the Industrial Era, the Information Era consists in a third important moment in the history of architecture. By embracing the digital condition, architects can draw and build solutions that would be hard if not impossible to achieve by means of analogical traditional processes. Having a natural repercussion in the built environment and at the building materials industry, it is important to survey the state of the art of the technologies that are motivating and supporting it.

2.6

REFERENCES

References that are not mentioned in this chapter’s text belong to the credits of the images used, and are cited in the “Illustration Credits” section of this thesis.

(1)

Addington, M. & Schodek, D. (2005): Smart Materials and Technologies for the Architecture and Design Profession, Achitectural Press, Burlington, MA.

(2)

Addis, B. (2007): Building: 3000 Years of Design, Engineering and Construction, Phaidon, New York, NY.

(3)

Barhydt, M. (1995): “Paperless Studio”, Oculus 57, No. 10, June 1995.

(4)

Bechthold, M.; Griggs, K; Schodeck, D.; Steinberg, M. (Eds.) (2000): New Technologies in Architecture. Computer Aided Design and Manufacturing Techniques, Harvard Design School, Cambridge, MA.

(5)

Bechthold, M.; Griggs, K; Schodeck, D. & Steinberg, M. (Eds.) (2003): New Technologies in Architecture II & III. Computer Aided Design and Manufacturing Techniques, Harvard Design School, Cambridge, MA.

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(6)

Bonet, J. (2000): The Essential Gaudi, Portic, Barcelona.

(7)

Cache, B. & Beaucé, P. (2007): Objectile – Conseque6ce, Institute for Cultural Policy, Springer Verlag Wien..

(8)

Callicott, N. (2001): Computer­Aided Manufacture in Architecture.

The Pursuit of Novelty, Architectural Press, Oxford.

(9)

Carpo, M. (2008): “Nonstandard Morality: Digital Technology and its Discontents”, in Anthony Vidler (Ed.), Architecture Between Spectacle and Use (pp. 127‐142), Sterling and Francine Clark Art Institute, Williamstown MA.

(10) Carranza, P.M. (2007): “Out of Control: The Media of Architecture, Cybernetics and Design”, in Kattie Lloyd Thomas (Ed.), Material Matters.

Architecture and Material Practice (pp. 151‐162) Routledge, Oxon.

(11) Chaszar, A. (Ed.) (2006): Blurring the Lines., Wiley‐Academy, West Sussex UK. (12) Cohen, J.L. (2005): Le Corbusier, Taschen, Koln.

(13) Duarte, J.P. (2001): Customizing Mass Housing: A Discursive Grammar for Siza’s Malagueira Houses, PhD thesis in Architecture, Design and Computation, Massachusetts Institute of Technology, Cambridge, MA. (14) Fernandez, J. (2006): Material Architecture, Architectural Press, Burlngton, MA. (15) Fernandéz­Galiano, L. (ed.) (2005): Herzog & de Meuron, AV n.114, July‐August, Madrid.

(16) Forester, T. (1987): High­Tech Society, MIT Press, Cambridge MA. (17) Friedman, M. (Ed.) (2002): Gehry Talks: Architecture + Process, Rizzoli, New York.

(18) Galli, M. & Muhlhoff, C. (2000): Virtual Terrani. CAAD in Historical and Critical Research, IT Revolution in Architecture series, Birkhauser, Basel.

(19) Garofalo, L. (1999): Digital Eisenamn. An Office of the Electronic Era, IT Revolution in Architecture series, Birkhauser, Basel.

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(20) Giedion, S. (1995): Building in France. Building in Iron. Building in Ferro­Concrete (1st edition: 1928), The Getty Center for the History of Art and the Humanities, Santa Monica CA. (21) Harper, N.G. (Ed.) (1972): Aplicaciones de las Computadoras en Arquitectura e Ingenieria, Editorial Shepsa, Barcelona (1st Edition: McGraw‐Hill, 1968) (22) Hart, S. (2003): “Innovation”, in Architectural Record No. 10, October, p.30‐35.

(23) Harves, J. (1971): The Master Builders. Architecture in the Middle Ages, McGraw‐Hill, New York NY. (24) Heyman, J. (1999): The Science of Structural Engineering, Imperial College Press, London.

(25) Kalay, Y.E. (2004): Architecture’s New Media, MIT Press, Cambridge MA. (26) Kilian, A. (2006): Design Exploration through Bidirectional Modeling of Constraints, PhD thesis in Architecture, Design and Computation, Massachusetts Institute of Technology, Cambridge, MA. (27) Kolarevic, B. (2000): “Digital Architectures”, in M Clayton and G.P. Vasquez de Velasco (Eds), Eternity, Infinity and Virtuality in Architecture, Proceedings of the ACADIA 2000 Conference, pp. 251‐ 256, Washington DC. (28) Kolarevic, B.

(2001):

“Digital Fabrication:

Manufacturing

Architecture in the Information Age”, in W. Jabi (Ed.), Reinventing the Discourse, Proceedings of the ACADIA 2001 Conference, pp. 268‐277, Washington DC. (29) Kolarevic, B. (Ed.) (2003): Architecture in the Digital Age. Design and Manufacturing, Spon Press, New York NY. (30) Kolarevic, B.; Malkawi, A.M. (Eds.) (2005): Performative Archiitecture. Beyond Instrumentality., Spon Press, New York NY. (31) Lamers­Schutze, P. (ed.) (2003): Teoria da Arquitectura. Do Renascimento até aos nosso dias., Taschen, Koln.

(32) Lindsey, B. (2001): Digital Gehry, Birkhauser, Basel.

(33) Lynn, G. (2004): Folding in Architecture (Revised Edition), AD – Architectural Design, Wiley‐Academy, UK.

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(34) Lynn, G. (1998): Folds, Bodies & Blobs. Collected Essays, Books by Architects, Bruxelles.

(35) McQuaid, M. (Ed.) (2003): Envisioning Architecture: Drawings from the Museum of Modern Art, The Museum of Modern Art, New York.

(36) Mitchell, W.J., Liggett, R.S. & Kvan, T. (1987): The Art of Computer Graphics Programming. A Structured Introduction for Architects and Designers, Van Nostrand Reinhold, New York.

(37) Mitchell, W.J. & McCullough, M. (1995): Digital Design Media, 2nd edition, Van Nostrand Reinhold, New York.

(38) Mitchell, W.J. (2001): “Roll Over Euclid: How Frank Gehry Designs and Builds”, in J. Fiona Ragheb (ed.), Frank Gehry, Architect, pp. 352‐ 363, Guggenheim Museum Publications, New York.

(39) Mori, T. (ed.) (2002): Immaterial / Ultramaterial. Architecture, Design and Materials, George Braziller, New York.

(40) Ojeda, O.R.; Guerra, L.H. (Eds.) (1999): Maquetas Virtuales de Arquitectura, Evergreen, Koln.

(41) Piedmont­Palladino, S.C. (Ed.) (2007): Tools of the Imagination.

Drawing Tools and Technologies from the Eighteenth Century to the Present, Princeton Architectural Press, New York NY. (42) Pimenta, E.D. (1991): Virtual Architecture ­ Virtual Environments and Architecture, ASA Art and Technology, UK. (43) Pine, B.J. (1993): Mass Customization. The New Frontier in Business Competition. Harvard Business School Press, Boston MA. (44) Pottman, H.; Asperl, A.; Hofer, M. & Kilian, A. (2007): Architectural Geometry, Bentley Institute Press, Exton PA. (45) Ritter, A. (2007): Smart Materials in Architecture, Interior Architecture and Design, Birckhauser, Basel.

(46) Schmal, P.C. (Ed.) (2001): Digital Real: Blobmeister, First Realized Projects, Birkhauser, Basel.

(47) Schodek, D.; Bechthold, M.; Griggs, K.; Kao, K.M. & Steinberg, M. (2005): Digital Design and Manufacturing. CAD/CAM Applications in Architecture and Design, John Wiley & Sons, Hoboken NJ.

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(48) Sebestyén, G. (1998): Construction – Craft to Industry, Routledge, London.

(49) Sebestyén, G. (2003): New Architecture and Technology, Architectural Press, Burlington MA. (50) Shea, K. (1997): Essays of Discrete Structures: Purposeful Design of Grammatical Structures by Directed Stochastic Search, PhD Dissertation in Mechanical Engineering, Carnegie Institute of Technology, Carnegie Mellon University.

(51) Shelden, D. (2002): Digital Surface Representation and the Constructability of Gehry’s Architecture, PhD thesis in Architecture, Design and Computation, Massachusetts Institute of Technology, Cambridge, MA. (52) Sutherland, I. (1963): Sketchpad, a Man­Machine Graphical Communication System, PhD Thesis in Electrical Engineering, Massachusetts Institute of Technology, Cambridge MA. (53) Tavares, D. (2004): Leon Baptista Alberti – Teoria da Arquitectura, Dafne Editora, Porto.

(54) Tschumi, B. & Berman, M. (Ed.) (2003): Index Architecture, A Columbia Book of Architecture, MIT Press, Cambridge, MA. (55) Yenne, B. (2002): Inside Boeing: Building the 777, MBI Publishing, St Paul, MN. (56) Van Berkel, B. & Bos, C. (1999): Move, UN Studio & Goose Press, Amsterdam.

(57) Watson, A. (Ed.) (2006): Building a Masterpiece: The Sidney Opera House, Powerhouse Publishing, Sydney (58) Wurster, C. (2002): Computers: An Illustrated History, Taschem, Koln.

(59) Zellner, P. (1999): Hybrid Space. New Forms in Digital Architecture., Thames & Hudson, London.

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Review of Relevant Digital Technologies

3.1

INTRODUCTION

The present chapter provides a synthetic review of the current state of digital technologies available to assist design and manufacturing processes in architecture. Knowing from the previous chapter that the extended space of architectural possibilities is dependent on the representation and construction methods selected by the architect, this review dedicates its attention to systematize the ones that are thought to be more capable of promoting such a condition.

The pursue of this challenge reveals an initial problem, concerning the boundaries of the research space. While the practice of computer drafting and visualization has been an incontestable reality in architecture today, there are digital processes initially developed for other fields that could be very interesting for architecture. Due to both reasons, the actual commercial market of digital solutions is very wide and diverse, and its disciplinary boundaries are impossible to be clearly defined. While architects can use the same software employed in the movies industry or in CNC equipment used in mechanical engineering, their meaning and purposes for each discipline can be quite different. Consequently, commercial industry and architects are dynamic and unstable entities that are constantly trying to know each other’s interests better, but they will never be fully coordinated. For this reason,

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evolution in this field tends to be fast and difficult to be fully captured.

Considering the ephemerality of commercial brands and their products, the present analysis emphasizes, instead, taxonomy and functional principles.

With this goal, it should be underlined that different disciplines tend to understand, assimilate and use technologies in different ways, which can lead to different evaluation criteria for its classifications. Dealing with the full range of CAD/CAE/CAM technologies many years before architects, mechanical engineers and, more recently, industrial designers, have produced many extensively detailed references about the subject.

Comprehensive references considered in this dissertation include Machover and Blauth (1980), Krouse (1982), Teicholz (1985), Zeid (1991) or Lee (1999).

During the last decades, these disciplines have been the great source for architects’ digital investigations, who have filtered that knowledge from the perspective of the particular operative and cultural characteristics of the discipline. With those precedents, architects surpassed the narrow scope of digital design processes to embrace wider studies and practices involving the whole spectrum of computer‐aided design (CAD), engineering (CAE) and manufacturing (CAM) technologies. Apparently later than the world of the professional practice, the theoretical recognition of the relevance of the whole family of digital technologies led William J. Mitchell in 1995 to include a new section about “Prototyping” in the 2nd edition of his seminal Digital Design Media book. Since then, relevant works produced in the field of architecture include, at the academic level, doctoral dissertations like those of Ruhl (1997), Rotheroe (2000), Yun (2001), Bechthold (2001), Duarte (2001), Caldas (2001) and Shelden (2002), while at the public level, comprehensive books written by Kolarevic (2003, 2005, 2008), Kalay (2004) and Schodeck et al. (2005).

Building on the top of these precedent works, this chapter’s review considers digital technologies in architecture oriented to: 

Design Understood as a broader concept involving all the representational tasks for the conception, development and communication of a design solution before its physical manifestation;

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

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Manufacturing Understood as the whole set of materialization processes that are necessary to accomplish the physical manifestation of a design object.

Within this framework1, “Design Technologies” are those concerned with the production and manipulation of all design information within the boundaries of the computer screens, while “Manufacturing Technologies” are those comprising the computer‐driven machines that are used to physically produce components, structures or even building parts directly from that information.

The following table [Fig. 3.01] outlines the general classification proposed2, based on references that are going to be further discussed in each part.

General Classification of Digital Technologies in Architecture Digital Technologies

Design

3.2.1 Computer Aided Design (CAD)  

Computerization Computation (parametric and algorithmic design)

3.2.2 Computer Aided Engineering (CAE) 

Finite Element Analysis (FEM)



Computational Fluid Dynamics (CFD)



Other energy and environmental analysis

3.2.3 Computer Aided Manufacturing (CAM)

Manufacturing



Numerical Control



Robotics



Process Plan



Factory Management

3.3.1 Additive Fabrication 3.3.2 Subtractive Fabrication 

2D



3D

3.3.3 Formative Fabrication 3.3.4 Robotic Assembly 3.3.5 Additive Construction

Figure 3.01 1

This division establishes a parallelism with the two moments of architectural practice that

oriented the discussion in the previous chapter – design and construction.

2

Although the three branches of computer technologies of digital design are conceptually very

clear, in practice, some current software packages tend to dilute their boundaries, by incorporating common capabilities (e.g., Catia, TopSolid, Solid Works, Digital project).

General classification of digital technologies in architecture.

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Supporting the analysis of the subject, this review is illustrated as much as possible with some of the practical experiments developed by the author at the following institutions:

Academic Institutions: 

IST‐UTL (Portugal), MIT (USA), IAAC and ESARQ‐UIC (Spain)

Industrial companies: 

LASINDUSTRIA (Portugal), VETOR3 (Portugal), FEYODESIGN (Portugal)

Author’s design practice: 

ReD Research+Design (Porto, Portugal and Barcelona, Spain)

Thanks to all these institutions, the experiments have covered large part of the digital design and construction technologies discussed here, allowing for testing some of their potentials and limitations. The theoretical framework of this chapter is thus informed and complemented by hands‐on knowledge.

3.2

DESIGN TECHNOLOGIES

3.2.1 Computer-Aided Design

Groover and Zimmers (Lee, 1999: 5) defined Computer‐Aided Design (CAD) technologies as those “concerned with the use of computer systems to assist the creation, modification, analysis, and optimization of a design”. The main focus of using CAD systems is to achieve the geometric definition of a design project. Throughout the last 40 years, many techniques have been developed to fulfill this goal. Ibrahim Zeid (1991: 15) resumes them as coming from three main areas: computer graphics concepts, geometric modeling and design tools [Fig. 3.02].

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Figure 3.02 The basic constituents of the CAD systems according to Zeid.

Nowadays, all these CAD constituents provide powerful capabilities to develop 2D drawing, 3D modeling and visual simulation and presentation tasks, but also analytical procedures for design evaluation and optimization.

Within these last ones, one may find what are called Computer‐Aided Engineering (CAE) technologies, which convoke areas of expertise adjacent to design. Although usually used by engineering specialists, it is not rare to see these CAE capabilities included within the realm of CAD in the literature.

In this case, engineering, as well as drafting, drawing, modeling or visualization, is understood as a subset of the global enterprise of architectural design3. Because the range of CAE techniques has expanded in recent years, and architects have become much more interested and familiar with them, they will deserve an individual attention in the next section4.

Following the conclusions of the previous chapter, the current review of design technologies is guided by an interest in computers beyond the scope of drafting and visualization productivity. To help framing this point of view, Terzidis (2006: xi) establishes a pertinent distinction between the concepts of “computation” and “computerization”:

3

This integration of CAE as a subset of CAD can explain why is common to use simply the

terminology of CAD/CAM, instead of CAD/CAE/CAM, to refer all the processes that support the total cycle of product development with digital technologies.

4

See section 3.2.2 of the current chapter.

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“While computation is the procedure of calculating, i.e. determining something by mathematical or logical methods, computerization is the act of entering, processing, or storing information in a computer or a computer

system.

Computerization

is

about

automation,

mechanization, digitization, and conversion (…) of entities or processes that are preconceived, predetermined, and well defined. In contrast, computation is about the exploration of indeterminate, vague, unclear, and often ill­defined processes; because of its exploratory nature, computation aims at emulating or extending the human intellect. It Is about rationalization, reasoning, logic, algorithm, deduction, induction, extrapolation, exploration, and estimation.”

In this context, throughout the historical perspective presented in the previous chapter, it becomes clear that computers have been and still are used today mainly under the paradigm of computerization. This mode of practice is tied to the understanding of the computer as a machine for representation, as discussed before.

However, it is the exploration of computational approaches that is behind the production of the majority of the most innovative buildings in contemporary architecture, especially, since Frank Gehry’s Guggenheim Museum in Bilbao (1997). The exploration of the digital convergence between powerful calculation capabilities with persuasive representation abilities to assist design conception, or in other words, the exploration of the computer as a machine for integrated calculation and representation, draws the basis for alternative design approaches that promise the emergence of architectural innovation.

Thus, Terzidi’s concepts are very useful to establish a sharp distinction, within current CAD technologies, between systems that promote:



Design Computerization



Design Computation

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3.2.1.1 Design Computerization

The actual landscape of commercial CAD software for building construction is dominated by systems that sustain the practice of computerization. The standard versions of current market leaders like AutoCAD or Microstation, and of recent programs like Rhinoceros, fall into this category5. Working with them, implies drawing and modeling operations for literal representation in the screen of pre‐conceived images formed in the designer’s mind.

Limited to the library of geometric primitives available in the program, the design evolves through a set of drawing and modeling procedures requiring the declaration of precise and definitive numerical attributes (i.e., coordinates, dimensions, angles). Without any form of embedded intelligence, the introduction of changes in the design implies the tedious task of erasing and redrawing operations. Like in the paper, a design representation in the screen is a static entity waiting for the designer’s action, to evolve through the addition and removal of drawing elements or parts. Sustained by the majority of commercial CAD software, this computer‐ based approach, which is defined by Mark Burry as “explicit design” (1997), does not add more to the experience at the old drawing board than the introduction of automation to increase the efficiency in the production of representations. For these reasons, it is argued that they offer limited capacities for changing the traditional nature of design thinking and conception in architecture.

Despite

these

creative

limitations,

designers

exploring

design

computerization systems may still be interested in taking advantage of other complementary digital design technologies, like CAE or CAM. With this goal, the quality of the geometric description and the efficiency of file conversion processes offered by CAD software are, therefore, two crucial aspects.

5

Progressively, these programs tends to incorporate some parametric possibilities, like

geometries that can be manipulated by grip points (i.e., polygons, spline curves or NURBS).

However, Terzidis (2006: xii) defends that their manipulation by the designer does not consist on acts of computation, justifying that “while the mathematical concept and software implementation of NURBS as surfaces is a product of applied numerical computation, the rearrangement of their control points through commercial software is simply an affine transformation, i.e. a translation”.

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For instance, a curved surface or solid in common software like AutoCAD has not an accurate geometric definition, but a faceted ‐polygonal‐ description of the desirable perfect curvature. Changing the system variables, the size of those facets can become smaller to achieve smoother curvatures, but the overall surface will still always be an approximation to the imagined one.

CAD software based on polygonal descriptions can originate several problems. For instance, working with curved geometries described in that way can be hard because files tend to be very heavy.

At the same time, the inherent editing and transforming operations available are very limited and their precision is not absolute. Finding a specific point on a curved surface could be an impossible task because the space for geometrical positioning depends on the polygonal resolution [Fig. 3.03]. This introduces another difficulty, in case the curved geometry is intended to drive digital fabrication processes. An apparently smooth representation on the screen can produce an undesirable faceted effect in the material object produced by additive or subtractive fabrication processes.

Figure 3.03 The problem of geometric approximation in CAD software. These images show the relative precision of the polygonal representation of a surface generated from four splines, which depends on the resolution specified in the software.

Advanced modeling technologies based on mathematical descriptions, like NURBS, can overcome these kinds of problems. Rhinoceros is one example of a surface modeler that can produce accurate geometric descriptions while offering a wide range of tools to draw, edit and transform almost any

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geometry, independently of its complexity [Fig. 3.04]. From this descriptive foundation, it can support many conversion options for the majority of the standard file formats used in CAE and CAM processes, like .STL or .IGES. However, despite these advantages, when comparing with its rivals, its 2D drafting capabilities are more limited.

Figure 3.04 Comparison between polygonal and mathematical descriptions. On the left, measurable points on a surface in AutoCAD can be found only in the vertices of the finite facets of its

resolution. On the right, an identical surface in Rhinoceros offers U and V

Thus, the combination of CAD systems, like Rhinoceros for 3D modeling with

coordinates to identify any

AutoCAD for 2D drafting, is a very common strategy in architectural offices

area. The control and

wishing to pursue more complex geometric explorations. Nevertheless, the essential of such practices is still mainly based on computerization principles.

3.2.1.2 Design Computation Systems

For the reasons already observed, the actual relevance of CAD systems for architectural design rely on their computational capacities. Within this field, we suggest the distinction of two different techniques: a) Parametric design b) Algorithmic design

While the later consists in the immediate translation of Terzidi’s definition for the design computation approach, it is suggested the inclusion of the former approach in this category because both processes take advantage of the calculation power to assist design representation. While parametric design is commonly experienced through specific modeling software packages, algorithmic design is engaged through code programming.

possible point on its surface precision is full on a mathematical description.

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Following, there is a brief explanation and analysis about the specificities of each technique, as well as the mention to hybrid approaches that have been introduced and explored in the recent years.

Parametric design

Parametric design is a computer‐aided design technique also known as associative geometry (Burry, 1997), relational modeling, variational design or constraint­based design (Monedero, 1997)6. Differently from the explicit design approach of computerization processes, it implies the representation of forms, whose geometry is controlled by parameters and associative relationships [Fig. 3.05].

Inspiring references for this way of thinking and acting can be found in

Figure 3.05

natural systems. For instance, the biologist D’Arcy Thompson (1961) showed

Simple parametric model in

in the beginning of the 20th century that observed differences in animals’

change from flat to twist

forms could be related and described through simple mathematical transformations [Fig. 3.06]. In a similar way, the discovery of the DNA, demonstrated how small changes in the common structure of information, describing the idea of a human, can control the generation of a wide world of differentiated results, in other words, of different men and women. In both situations, it is decisive to verify that design exploration moves from a static and metric territory to a variable and topological one.

6

Mark Burry and Javier Monedero’s papers presented at the eCAADe conference in 1997 are

recommended references for an introduction to the use of parametric design techniques in architecture. In 2003, the author presented a paper at CAADRIA with Marta Male‐Alemany where parametric modeling implications in architectural design where discussed (Malé‐ Alemany & Sousa 2003).

TopSolid of a surface that can configuration. Developed by the author, the model adjusts itself automatically to every new set of values introduced in the parameters.

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Figure 3.06 With this image D’Arcy Thompson shows how a Scarus sp. can be transformed into a Pomacanthus by means of a geometric deformation.

In the computational realm, to take advantage of parametric design software, the designer must shift his conceptual interest. Instead of thinking in a particular design form with a fixed geometry, he has to think about a design intention based on a flexible ruled‐based geometry. This idea of a design is captured and represented in a parametric model, which has the ability to adapt its geometry into variable possible configurations. To control this exploration the designer plays with two types of parameters ‐ variables and constraints. While the former consists on values that can be changed at any time (e.g., length, area, radius, angle) the later consists on geometric (e.g., parallel, perpendicular, tangent) or numerical conditions (e.g., minimum and maximum acceptable values, mathematical expressions) that introduce rules and limitations to the model’s variational behavior.

In this context, the designer’s acceptance of indeterminacy as a positive part in the process is expressed in his choice of variables, which defines the spectrum of design flexibility. However, this freedom is simultaneously calibrated by the careful selection of constraints, which traduce the designer’s rules, or criteria, to assure the essential of his intention is not lost when exploring the parametric variation possibilities. The success of a parametric model depends thus on a balanced negotiation between its degree of freedom and regulation. The investigation Flexible Housing Research Project, developed by the author for his masters in Genetic Architectures in 2002, illustrates some of the features inherent to parametric thinking and modeling in architectural design [Fig. 3.07].

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Figure 3.07 Parametric design strategy for customized houses.

Concept, rules, parametric model, variations, parameters description, render of a solution.

According to the parametric design software capabilities, the user can have usually four different ways of operating with design parameters [Fig. 3.08].

They can be by: 

Direct manipulation of the geometries in the screen;



Filling the parameters by typing their values in the screen;



Using external applications like Excel spreadsheets to feed their values;



Describing parameters to be based on the geometric attributes of other design parts7.

7

This technique consists in using the geometric attributes of some design parts to implicitly

inform others. For instance, the height of a parametric model of a beam can be defined in proportion to its length, following a mathematically relation. Thus, any change introduced by the designer in the length value of the beam, will automatically produce a change of its height,

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Figure 3.08 Interaction with parametric model. In the author’s Flex‐H model, the user can drag the geometry in the screen, fill the parameters in the TopSolid table or use the Excel file. At the same time, some parameters are programmed to drive other parameters.

Along with parameterization, associative geometric possibilities are a key‐ aspect of parametric design approaches. The complexity of a parametric model evolves through the construction of a hierarchical chain of interdependent relationships between different design parts, or even, between different design files. Its structure is based on multi‐scalar relationships where a small change in one parameter can be propagated to the whole model following the tree of geometric associations defined.

This capacity to automatically react to the input of new sets of information raises another powerful aspect of working with parameters, which consists in the possibility for representing information from different fields to affect or inform the model’s adaptive behavior. In this manner, input values can be associated to structural formulas, aesthetical principles, environmental factors, economical requirements, etc8.

Another relevant aspect of these digital environments consists in the mathematical description of the geometries, which is suitable for producing digital models with sufficient accuracy to drive digital engineering and manufacturing processes. Very often, parametric design software is also part of larger software packages that can include, for instance, drafting, rendering, CAE and CAM facilities. This facilitates not only a digital continuity but also following that previously established rule. In this case, the rule could be associated to engineering requirements and equations.

8

See the example described in the previous footnote.

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the extension of parametric and associative behavior throughout the whole product cycle development. Design conception, engineering, manufacturing and documentation can be efficiently managed with these computational systems.

Early pioneers in architectural practice exploring parametric design techniques, include Bernard Cache, Mark Burry and Frank Gehry’s office during the 1990’s. With the beginning of the present century, parametric design has become increasingly popular in both academic and professional realms. Originally developed for the mechanical engineering field, both CATIA and TopSolid9 are examples of parametric design software currently used in architecture. However, the recognition of the relevance of this technique led to the emergence of two applications aiming to be more suitable to address the design specificities of architecture. One is Digital Project, a software developed by Gehry Technologies based on CATIA, and the other one is Generative Components (previously Custom Objects), developed by Bentley Systems [Fig. 3.09]. Autodesk’s Revit is also a software that integrates parametric technology. However, its main focus towards BIM practices seems to value more the automation of design and documentation over some conceptual and modeling possibilities that are better addressed with the previously mentioned software, or even, with the Autodesk’s Inventor, which is the company’s parametric design software for mechanical engineering10.

9

TopSolid is a parametric design software produced by the French company Missler that was

introduced in architecture by Bernard Cache. Nowadays, this software is used in architectural schools like ESARQ‐UIC and IAAC in Barcelona, the Berlage Institute in Rotterdam or the University of Pennsylvania in Philadelphia.

In its Autodesk’s official brochure, the Revit Architecture 2010 software is officially

10

presented in this way: “(…) Purpose­built for building information modeling (BIM), Autodesk Revit Architecture provides superior support for sustainable design, clash detection, construction planning, and fabrication, while helping you work collaboratively with engineers, contractors, and owners. Any and all design changes along the way are automatically updated throughout your evolving design and documentation, making for more coordinated processes and reliable documentation.”. Brochure available at: http://images.autodesk.com/adsk/files/revit_architecture_2010_brochure.pdf (Accessed: 19 July 2009)

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Figure 3.09 Personal experiment with Generative Components.

Parametric model of a complex shape with a torsion.

On its structure (top), it is applied a variable component that can change dimensions (bottom).

My first contact with this technique started in 2002 and have consisted mainly in the use of the software TopSolid. Through successive experiments developed since then both in academia and practice, it became possible to acknowledge the usefulness of parametric design approaches for: 

developing modeling approaches to generate a family of customized solutions11;



refining geometrical aspects of a singular design through the exploration of its possible variations12;



implementing associative design and fabrication strategies to support interactive modes of practice between conception and making activities13;

Personal experiments include the Flexible Housing Research Project (Flex‐H) develop for my

11

Masters in Genetic Architectures at ESARQ‐UIC (Barcelona, 2002), or the Research Studio conducted with Marta Malé‐Alemany for the Master in Advanced Architecture Program at IAAC (Barcelona, 2008) dedicated to develop “Parametric Houses”. In all these cases, the goal was to define a parametric model that could generate customized design solutions for singular houses.

Personal experiments include works developed in practice by ReD (with my partner Marta

12

Malé‐Alemany), like the XURRET System, a urban furniture project where the three dimensional texture of the benches was studied using a 2D parametric model, or the DRAGORAMA project where the generation of an ornamental texture for a set of acrylic panels was defined parametrically considering distance variables between the location of the panels and the surrounding doors.

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The set of experiments carried out unveil that the key‐aspect of parametric models lies in their affirmation as flexible representations that allow for controlled and informed design exploration towards the development of either a singular optimal solution, or a family of customized differentiated ones. The visual nature and the real‐time interaction of the modeling environment, represents major factors to explore computational processes in architecture.

By thinking and designing parametrically, architects go beyond static representations to instrument the calculation power of the computer as a generative tool, thereby achieving a digital experience that could not be offered by analogical tools. Unlike the digital models built under the paradigm of computerization, parametric models resemble organic machines designed and programmed by the architect for performing calculations – geometric adaptations‐ towards the production of results – variations of a design intention. With them, erasing and redrawing operations are replaced by adaptive behavior, which permit to keep open several design possibilities until later phases of the design process.

However, due to the hierarchical structure of parametric models, with parent‐child dependencies, substantial changes in their structure can become hard to accomplish. For instance, the parametric hierarchy usually involves a global design –the whole‐ composed by a set of local components –the parts‐ ruled by associative relationships. In such system, although some top‐down and bottom‐up behavior can be introduced, it is very difficult to change some design definitions without compromising the model’s hierarchy. On one hand, in qualitative terms, the design’s geometric structure is very difficult to be changed during the process. The flexibility of the parametric design exploration has a topological nature, where different variable solutions are obtained by means of differentiation processes. In some circumstances is possible, however, to simulate the generation of apparently distinct solutions by tricking the software. On the other hand, the quantitative dimension of the design exploration has also some restrictions. Both the number of designs and the number of its components are hardly changed automatically Personal experiments include the works developed in the CAD/CAM studio oriented with

13

Marta Malé‐Alemany in the Master in Genetic Architectures program at ESARQ‐UIC in 2003, where the students were challenged to develop associative relations between design and fabrication information. This academic experiment was then documented in a paper presented at CAADRIA 2003 (Malé‐Alemany & Sousa 2003)

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throughout the process. From these points of view, the system seems a bit closed in qualitative and quantitative terms.

Nonetheless, although the space of design exploration has that intrinsic topological order, the interaction with the parametric model can produce unexpected results. Having the capacity to surprise the designer, they reveal to be an interesting media to support creative exploration and, therefore, to create conditions to develop projects in novel ways. For all these reasons, it is argued the inclusion of this software‐based technique in the realm of computational design approaches.

Algorithmic design

A different kind of computational design processes consists in algorithmic approaches attained by means of computer programming14. The core of these processes lies in the notion of algorithm, which is defined by Terzidis (2006: 15) as “a process of addressing a problem in a finite number of steps”.

Instead of creating and manipulating geometries directly on the screen, the architect writes computer instructions specifying a set of geometric definitions, variables and logical functions, using programming languages.

Due to its memory and data processing resources, the computer supports iterative or recursive capabilities which are very powerful for the implementation of algorithms to solve given problems. Although architectural design can be considered as a problem‐solving activity, architectural problem’s does not have a single‐optimal solution. Thus, unlike other disciplines (e.g., structural engineering), the selection and use of algorithms in architecture should be carefully made to negotiate the scientific/artistic, objective/subjective or predetermined/unpredictable The history of architecture shows that the exploration of algorithmic design strategies does

14

not represent an absolute novelty. Indeed, it is possible to find many examples about the formalization of architectural thought and design by means of design rules systems. As Kalay (2004: 267) says, “habitual design rule systems are as old as Vitruviu’s De architectura (c. 28 BC), Alberti’s De re aedificatoria (printed 1485), Vignola’s Regola delli cinque ordini d’architettura (1562), and Palladio’s I Quattro libri dell’architettura (1570).” To know more about this, see also Mitchell’s book (1990), The Logic of Architecture, where he provides an extensive analysis of this theme, discussing and illustrating the relation between cognitive and computational processes in architectural design.

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dichotomies, which are intrinsic of the discipline’s nature and richness15. To help enlighten this discussion, it is interesting to follow Terzidis’ suggestion (2006: 38) of using the term “problem­addressing” than “problem solving”.

As seen in the previous chapter, early explorations of CAD in architectural practice implied the use of programming to develop CAD routines and applications towards drawing automation and numerical calculation goals.

But in the academic realm, there have been consistent research works about computational techniques since the 1970’s that could be interesting for architectural design. George Stiny, William Mitchell or John Frazer, are some researchers that envisioned the architectural interest in computational techniques like L­Systems, Cellular Automata, Shape Grammars or Genetic Algorithms. However, the implementation in practice of such systems only achieved a recognizable dimension with the beginning of the present century.

The possibility of avoiding programming stand‐alone applications from scratch, by exploring scripting languages increasingly available in CAD software, encouraged architects to embrace the algorithmic world of computational design16. Making references to the built‐in programmed resources, like primitives and functions, it becomes easier for a designer to write a piece of code ‐the script‐ and thus expanding the capabilities of the original software and addressing customized design strategies.

Algorithmic design can be used for many purposes. Besides the production of macros or actions to speed‐up and automate repetitive tasks, it can be also a media to support new design experiences. On the one hand, similarly to parametric design, the description of design geometries can be controlled by variables, thus opening the possibility for topological variation exploration.

But, on the other hand, the introduction of certain algorithms, like conditional expressions, can produce generative behavior. Furthermore, the exploration of recursive functions can incorporate an evolutionary Naturally, this argument represents a holistic vision of the design process. In some particular

15

parts of the project, the architect can face the necessity to resolve specific problems that can be successfully represented and solely solved by computer programs. However, what is in discussion here is the use of computers to address creative design tasks where this type of optimization problem is not necessarily central and unique.

There’s some discussion about the terminology between a program and a script. A commonly

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accepted explanation says that a program is a compiled set of computer instructions that work as a stand‐alone application. Differently, a script consists on a set of instructions that run inside of a host software. While programming needs to write all the functions needed for its performance, scripting can take advantage of existent programmed functions of the host software, minimizing the need to program everything.

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dimension in the script, thus integrating time as a design variable. In all cases, the computer’s calculation power is instrumented as a generative design tool with the capacity for extending human representation and cognitive capabilities. Duarte (2001) research work on Siza’s Malagueira houses, exemplifies how a digital design system can incorporate design rules in such a way.

Today, algorithmic design approaches are becoming increasingly popular both in practice and academics, mainly through scripting. Remarkably, the interest and use of this technique cross the whole spectrum of architectural practices, ranging from large firms like SOM or KPF, signature‐architects like Frank Gehry, Norman Foster or Zaha Hadid, but also small studios and young architects like Andrew Kuddless or Chris Bosse. Some of the most used languages are: 

AutoLISP (AutoCAD)



MEL (Maya)



MaxScript (3D Max)



Rhinoscript (Rhinoceros)

The beginning of this dissertation provided my first contact with algorithmic design strategies, which has consisted mainly in the use of AutoLISP, running in AutoCAD, and Rhinoscript (VB Script), running in Rhinoceros. Since then, a series of experiments with this computational technique, both in academics and in practice, gave a progressive practical insight about some of its benefits and limitations.

The first evidence consisted in the confirmation that scripting is indeed an efficient method for expanding the possibilities of standard CAD software.

For instance, parametric and generative behavior can be easily incorporated in the design process using packages based on explicit drawing and modeling procedures.

Written in AutoLISP, the TriSURF script was developed during my PhD studies at IST‐UTL to explore and evaluate this possibility17. Running in AutoCAD, this script has codified a series of geometric rules that offer variable geometric triangulation strategies as a means to rationalize and fabricate curved surfaces The TriSURF script was the result of a sequential series of assignments in the Computer

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Aided Design II class taught by José Pinto Duarte at IST.

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out of planar components. Depending on the geometric input and some constructive decisions, the TriSURF can automatically generate an infinite number of solutions surface triangulation [Fig. 3.10].

Developed by ReD, the FLUOScape installation was a professional project

Figure 3.10

where scripting techniques where employed in a real context [Fig. 3.11].

The TriSURF script. By

Aiming to create an inverted topographical effect by hanging almost 600 different pieces of fabric from the ceiling, it became evident that traditional modeling approach would not be sufficient for solving this intention. Thus, using AutoLISP, I could wrote a script –FluoSCRIPT‐ to capture the studio’s design intention and enhance it through computation. By inferring the individual dimensions of the pieces from their distance to selected reference points in space, the script generates 3D models of all the pieces its individual contour for informing further CNC laser‐cutting process. Working with code allowed to easily incorporate other functions like individual labeling and area measurement. Knowing the material price it was automatically quoted the estimated material price of each solution explored. The use of this

managing variables and data storage in lists, this scrip allows generating triangulated surfaces.

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approach revealed to be very flexible. Taking about 5 minutes for calculating and drawing a complete solution, it was possible to test new ones, or incorporate changes, until the deadline for initiating fabrication.

The development of ruled‐based design strategies through scripting permit expanding the world of design exploration allowed by working with

Figure 3.11 The script developed for the FluoSOFT installation,

parametric models, through the exploration of a higher degree of generative

automatically generating 3D

capabilities. Indeed, topological variation can be attained but also surpassed by

model, flat contours for

non‐topological modes of variation, which still continue to be ruled by a single

area calculation (top). Foto of

common design representation, in this case, the script. This possibility can open new avenues for design development. For example, when facing the challenge of designing multiple architectural objects, while computerization techniques encourage repetition procedures and parametric design promotes differentiation strategies, algorithmic design can sustain a higher degree of variation where the solutions can be radically different from each other [Fig. 3.12].

cutting, individual labels and the installation at the Kunsthaus Graz (bottom).

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Figure 3.12 In this algorithmic definition done with Grasshoppers, the proximity of an external point to the points of a grid creates objects with different sizes, performing both topological and generative behavior.

Although Grasshoppers is a visual programming environment, and not truly scripting, this experiment is brought here to show the kind of behavior that can be attained with scripting.

The top row shows differentiation occurring with spheres, but after a certain distance there is a topology break, which generates boxes instead. On a larger distance, the system starts to eliminate the boxes that are far.

The bottom row shows at any position of the external point,

other variations can occur.

The grid can be shaped in 2D

This kind of experience is very powerful and, like topological variation, it can

adaptation of the objects.

and 3D, while generating an

be also observed in natural systems. For instance, based on scientific

Furthermore, the number of

descriptions, Manuel DeLanda18 refers that water is an element that can be

any time. This experience

objects can also be changed at

found at different gradual temperatures in nature. However, at two specific

shows the powerful of

values, 0 and 100 Celsius degrees, a change in its molecular structure occurs,

perform both quantitative

producing a radical change of its condition, stepping between solid, liquid and gas states. In a similar way, design exploration can integrate phase transition points where its topological structure can be totally transformed to better suit certain design goals. In this case, all these different solutions can be the outcome of a single codified design system. In supporting such variety, this technique still keeps a sense of economy in the design process, as each of those possibilities does not come from a set of individual modeling efforts, but actually from a single common programmed one.

During my visiting scholar period at the University of Pennsylvania, I attended Manuel

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DeLanda’s “The Philosophy of Materials and Structures“ class, where this story was acknowledged. Manuel DeLanda is a philosopher with a deep interest in Giles Deleuze philosophy and in scientific, materialistic and computer science discourses. One of his major contributions has been the remarkable way he has bridged those multidisciplinary subject with the field of architecture.

algorithmic strategies to and qualitative variation.

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During the design process, the introduction of significant changes in the written structure of the script can be easier than in the rigid hierarchical chain of parametric models. On the one hand, the code as a medium allows for flexible edition of the qualitative design definitions. For example, geometric entities can be altered by adding, editing or removing some code parts, which can be easily done through trivial operations like writing, erasing, copying or pasting. On the other hand, managing scripted variables and data storage lists makes it more flexible to overcome the quantitative limitations founded in parametric models.

Although scripting can be very useful for clear “problem‐solving” situations, through deterministic and optimization algorithms, it can also support what Terzidis suggested as “problem­addressing” activities. As an example, we can consider the following scenarios. First, instead of running continuously, the script can contemplate some pause moments to ask for user’s input (e.g., values for variables, geometric information, design selections) in order to drive the rest of the generative process. This option can be interesting by allowing the user to observe certain results in order to make decisions to inform the continuation of the script [Fig. 3.13]. Different architects will reach different results, according to their own design interests.

Another situation consists in the exploration of stochastic or random algorithms to generate unpredicted and non‐deterministic results. This approach can also include heuristic algorithms to perform design evaluation tasks that can substitute or complement designer’s own evaluation of the process. Integrating time as a variable for iteration, design solutions can be refined from certain perspectives or goals throughout that process. In their PhD dissertations, Shea (1997) and Caldas (2001) have developed comprehensive work that demonstrate the potential of using digital design systems that incorporate optimization algorithms for, respectively, structural, and daylight use and energy conservation goals.

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To conclude this overview about this algorithm design techniques, it is

Figure 3.13

important to highlight that the nature of the architect’s interaction with the

By managing variables and

programming media consists in a symbolic procedure that requires some

TriSURF scrip allows for

data storage in lists, the

abstraction, both in thought and in action. However, its practice can be a

global automatic behavior,

truly pleasant activity and a source of joyfulness like, for instance, the

decisions. After running the

and local user‐defined

experience of hand drawing is commonly acknowledged.

generation of a triangulated

of specifications, the script

Finally, despite the discussed interesting capabilities of design programming, an important limitation should be here referred to. Considering the complexity of architectural buildings, algorithmic strategies are insufficient to conveniently tackle it as a whole. While a digital parametric model can efficiently incorporate progressively more and more design information, sometimes at the expense of losing some flexibility, code is a harder medium to describe all design geometry and data in a building. Therefore, current implementations in practice are focused on small‐scale designs, like installations, or specific moments, like conceptual design, or parts of the design, like facade design.

Towards hybrid Computational Strategies

Summarizing the previous discussion, the singularities of each approach can be resumed in the following table [Fig. 3.14], which serves to understand each one’s advantages and limitations, but also complementarities.

surface according to a pre‐set permits choosing specific areas to create 3D pyramidal shapes or openings.

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Computational Design Approaches

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Figure 3.14 Comparison table between

Environment Medium Action

Parametric

Algorithmic

Graphic Interface

Text-based Interface

Geometric Representation

Code

Modeling

Programming / Scripting Topological

Behavior

Topological Generative*

Experience Feedback

Visual

Symbolic

Synchronous

Asynchronous

The relevance of both approaches is witnessed by Mark Burry (2003), when he defends that “the new generation of designers require to be versed in at least one of these techniques – parametric design and design computer programming – as a new definition of design skill essential for full participation in today’s environment”. Considering the specificities of both approaches, some initiatives have been launched during the last few years to bridge these possibilities.

On one hand, taking advantage of advanced modeling capabilities, the possibility of scripting within parametric design programs like Digital Project or TopSolid started to be explored. While this type of software is suitable for modeling a complete building and managing its inherent information, the possibility of scripting can expand the scope of creativity and efficiency in certain parts or moments of the design process.

On the other hand, to make friendlier computer programming procedures, some software developer companies and architects have started to integrate advanced algorithmic capabilities in digital design applications. For instance, under Robert Aish orientation, Bentey Systems has developed Generative Components (previously Custom Objects) which adds interesting generative capabilities to parametric design. KPF or Norman Foster are some of the offices that have used this program, which has been promoted within universities worldwide by a group of architects and researchers entitled as

parametric and algorithmic design approaches.

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SmartGeometry Group. In a similar way, Grasshopper (previously Explicit History), developed by David Rutten, is a recent plug‐in that introduces parametric and algorithmic design possibilities inside Rhinoceros (Fig. 3.14).

Architects like Zaha Hadid or engineering firms like Bollinger & Grohmann, are some of the users of this increasingly popular application.

In both cases, interesting possibilities usually attained by code are now being implemented and tested with visual interfaces that show responses in real

Figure 3.15 Experiment with Grashoppers. Modeling of a

time, configuring a tendency to what have been called as “visual

trefoil geometric shape,

programming”.

which is parametrically

populated with a shape, which can be changed at any

moment in the definition.

this approach to consider

3.2.2 Computer-Aided Engineering (CAE)

As defined by K. Lee (1999: 7), Computer Aided Engineering (CAE) technologies refer to the “use of computer systems to analyze CAD geometry, allowing the designer to simulate and study how the product will behave so that the design can be refined and optimized”. As seen in the previous chapter, with the example of the Sidney Opera House project, due to the mathematical nature of its practical and theoretical procedures, engineering disciplines became acquainted very early with the use of computers. Since then, CAE

This proves the flexibility of changes throughout the design process. (José Pedro Sousa, 2009)

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technologies evolved in several directions. On the one hand, the computational power have increased and enabled the development of more complex calculations, integrating new scientific advancements like, for instance, at the materials and structural level. On the other hand, CAE technologies have progressively employed three‐dimensional information both as an input for calculation and as an output for graphic simulation and visualization.

With these advancements, CAE technologies can thus use three‐dimensional CAD models to enable the digital study of particular engineering scenarios with a higher degree of complexity that could no be solved with conventional standard formulas and methods. Simultaneously, that model became also the medium to graphically illustrate the simulation of the engineering analysis.

Complementing

traditional

numerical

information,

these

visual

representations dramatically facilitate the comprehension of the phenomenon, especially in complex scenarios [Fig. 3.15].

Naturally, the use and evolution of CAE technologies have been conducted by engineers, who saw them as an alternative method for the traditional necessity to produce physical models and tests to validate theoretical formulations19. In this way, CAE supports an extreme reduction of costs and the increase of speed. However, their impact and interest in contemporary architecture deserves to be mentioned in this review. When during the 1990’s architects started to explore complex forms in architecture using advanced CAD processes, it became clear that unconventional forms required unconventional engineering techniques to be efficiently studied. Because “it is not possible to obtain analytical solutions for many engineering problems” (Desai & Abel, 1972: 3), CAE technologies provide interesting technical answers for architect’s desire in expanding the world of design possibilities [Fig. 3.16].

Although CAE technologies allow to simulate and perform digitally a wide range of physical

19

tests, like structural or fluid dynamic analysis, engineers warn that testing with physical models shouldn’t be abandoned. For instance, Frei Otto (2008: 41) warns that the computational analysis is not sufficient. Nonetheless, he admits that all his buildings have been calculated with computers since 1965.

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Figure 3.16 Structural analysis of the Swiss Re building, designed

by Norman Foster. The 3D graphic representation contributes for a better understanding of complex engineering phenomenon.

Among the most used and promising CAE technologies used in building construction, the following ones should be highlighted: 

Finite Element Analysis



Computational Fluid Dynamics



Other energy and environmental analysis

3.2.2.1 Finite Element Method (FEM)

The Finite Element Method (FEM)20, is one of the most relevant and widely used CAE techniques.

Its principles are resumed by Brauer as: “one [method] wherein the difficulty of mathematically solving large complex geometric problems (say doing the stress analysis of a Boeing According to Robert Cook (1981: 5‐6), the history of the Finite Element Method has its roots

20

in research studies conducted in 1906 and in a work developed by a mathematician called R. Courant published in 1943. Because there were no computers at that time to perform the inherent hard calculations, this study did not have a practical implication until later. The turning point happened in 1956 with the paper “Stiffness and deflection of complex structures” written by M. J. Turner, R. W. Clough, H. C. Martin and L. J. Topp, where a broader definition of the method was explained, now, within the engineering field. Since then, the adoption of FEM has grown exponentially, being today a widely respected method by both academicians and professionals. As a term, the Finite Element Method was coined in 1960.

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747) is transformed from a differential equation approach to an algebraic problem, wherein the building blocks or finite elements have all complex equations solved for their simple shape (say a triangle, rod, beam, etc.)“ (Brauer, 1988: 4)

To perform a FEM analysis, a design model is represented as an assemblage of smaller parts – the finite elements ‐ through discretization modeling processes. Acting from part to whole, the analysis and combination of the solutions obtained at the local level indicate the solution at the global level.

In his operations, although the method is based on simpler calculations, the amount of data taken in the analysis can be highly massive, because it depends on the considered number of elements under study. For this reason, “the finite element method is essentially a product of the electronic digital computer age” (Desai & Abel, 1972: 4).

Due to this reason, FEM is suitable for analyzing many different engineering problems like stress, deformation, fatigue, heat transfer, magnetic field distribution, fluid flow, etc. Current FEM analysis applications include SAP2000, ANSYS, Nastran, Abaqus or Autodesk ROBOT (former Robot Millenium). However, FEM analysis have been also incorporated within larger parametric software packages like in CATIA, TopSolid (TopCastor), or SolidWorks (Cosmos).

With obvious application for material and structural simulation, FEM analysis have been a determinant factor for the current emergence of built works exhibiting complex forms. The curvilinear shape of Peter Cook’s Kunsthaus Graz, the angulated structural walls of the OMA’s Casa da Música [Fig. 3.17] or the smooth ones of Zaha Hadid’s Phaeno Science Center, are some examples of different irregular buildings that became reality due to FEM structural analysis developed, respectively, by engineer firms OSD (Office for Structural Design), Ove Arup + AFA Consult, and AKT (Adams Kara Taylor).

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As “engineering programs are becoming more CAD­like” (Chaszar, 2006: 12),

Figure 3.17

architects feel tempted to jump into FEM software. Although the correct set‐

the Casa da Música in Porto,is

up and interpretation of the results still needs to be done by specialists, it is possible to note a tendency of introducing architects in the exploratory use of

Designed by Rem Koolhaas, an irregular building which structural behavior could not be evaluated following

this method to get some early engineering indicators and drive creative

conventional calculating

endeavors. For instance, in the Master program in Emergent Technologies at

methods, which led to the

the Architectural Association, students have explored FEM analysis with the

analysis (left).

help of engineering specialists, to assist the generation and evaluation of their innovative design proposals.

3.2.2.2 Computational Fluid Dynamics (CFD)

Another digital analysis technique that started to be recently explored in building design, is the Computational Fluid Dynamics (CFD). As explained by Ali Malkawi (Kolarevic & Malkawi, 2005: 88), CFD “applies numerical techniques to solve Navier­Stokes equations for fluid fields and it provides an approach to solve the conservation equations for mass, momentum and thermal energy”.

With this goal, CFD takes design models to produce dynamic representations to simulate and study unstable fluid conditions, like air flow and natural ventilation, temperature distribution, building material emissions, fire and smoke propagation or noise prediction. Requiring expert knowledge, this tool is hard to be rigorously mastered by architects. However, CFD’s graphic possibilities are an invitation for interdisciplinary collaboration. Under the

development of finite element

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guidance of Ali Malkawi, architecture students have been introduced in CFD at the University of Pennsylvania. In practice, many engineer firms, like Buro Happold, have employed CFD analysis to predict the future building performance [Fig. 3.18].

Figure 3.18 CFD model of the interior of the Experimental Media and Performing Arts Center, of the Rensselaer Polytechnic Institute, designed by Nicholas Grimshaw. The simulation studies the air velocity of the ventilation system.

Current CFD software includes ANSYS products, like CFX or FLUENT, which has a specific version for CATIA.

3.2.2.3 Other Energy and environmental analysis

Aligned with current sustainable concerns that dominate the contemporary world, there is a growing commercial and professional interest about CAE techniques that enable the development of environmental and energy analysis in building design.

Through interactive representations, software like Energy Plus or ECOTECT support an understanding of the performance of a particular building design under changing environmental conditions or energy factors. With these tools, it is possible to develop a wide range of analysis like shadows, reflections, shading, solar, lighting, acoustic, thermal, ventilation and air‐flow or energy consumption, considering changing conditions like day and year climate variation [3.19].

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Figure 3.19 Shadows and winding studies conducted by A. Texeira to study the performance of a building in two different places.

Its easiness of use and its ability to simulate building performance and document it with suggestive and detailed graphical representations, have attracted many architects to explore computer‐based environmental and energy analysis, both in leading architecture schools worldwide and architectural offices. Recent acquisition by Autodesk of ECOTECT can be understood as a sign of the growing importance of these tools in architecture today.

3.2.3 Computer-Aided Manufacturing (CAM)

Computer Aided Manufacturing (CAM) technologies refers to “the use of computer systems to plan, manage, and control manufacturing operations through either direct or indirect computer interface with the plant’s production resources” (Lee, 1999: 6). While CAD is mostly concerned with the design geometry definition and CAE with its performative optimization, CAM

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technologies are concerned with its materialization. According to Lee (1999: 6), and Krouse (1982: 48‐54) they are centered on four main areas: 

Numerical Control (NC) – to drive fabrication processes like drilling, cutting, milling, sawing, turning, folding, rolling, bending;



Robotics – to program the action of robots to perform fabrication tasks like welding, assembly or carry equipment;



Process Planning– to plan the sequence of steps required to produce parts and assemblies in the factory;



Factory Management – to tie together the other CAM areas to coordinate operations of the entire manufacturing facility.

The first application area is the most mature one. The birth of CAM technologies is indeed intimately connected with the emergence of Computer Numerically Controlled (CNC) machines during the 1960’s. Until then, only experienced programmers could write the numerical instructions (NC) required for fabricating parts in automated machines, directly from the interpretation of design drawings. Their NC programs had then to be tested in the machine to check for possible errors and refinement necessities. This traditionally manual and iterative process was hard, time‐consuming and, therefore, expensive, especially when dealing with complex geometries21.

The advent of CAM technologies in the 1960’s and 1970’s radically changed this condition. In this digital manufacturing process, the operator just needs to supply a small set of information, while the CAM software quickly generates the majority of the required NC instructions directly from the CAD geometry file. Displaying an interactive graphical interface, CAM software makes possible to simulate the animation of the entire manufacturing process. This function is very helpful as the operator can preview the final result before running the machine and using the physical materials. At the same time, he can also prevent several problems like the collision between the tool and the material, or the machine, during the manufacturing process.

The complete generated NC code is post‐processed and compiled in a digital file by the CAM software, which is sent to the machine’s computer to drive its Krouse (1982: 92) explains that manual NC programming could only comprise the

21

manufacturing of simple shapes, like planes, cones or spheres, which could be mathematically described through known equations. In contrast, due to their irregular geometry that might not follow mathematical equations, sculptural surfaces “were formerly considered to be impractical to machine with NC” so, therefore, CAM technologies have opened a way for the materialization of free‐form surfaces.

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operation. In this context, without the mediation of printed documents and human interpretation, this CAD/CAM connection between design and manufacturing configures what is commonly called as a file­to­factory practice22.

The second area encompassed by CAM technologies concerns robotic programming. Increasingly inhabiting factories over time, industrial robots, as explained by Krouse (1982: 52): “are automated manipulator arms that perform a variety of material­ handling tasks in the CAD/CAM systems. Robots may select and position tools and workpieces for NC machine tools. Or they may carry equipment or parts between various locations on the shop floor. They also may use their mechanical hands (called end effectors) to grasp and operate drills, welders and other tools.”

Until the emergence of CAM technologies, the operators programmed robots by leading them through every move required, which become consequently recorded. Constituting a time‐consuming process, this human intervention is often a source of errors. Overcoming these limitations, CAM systems sustain a more flexible and intelligent way of programming robots, allowing for the automatic determination of grip points and motion paths directly from the geometric database. The development of advanced programming languages and the integration of artificial systems like sensors and visual detection has been permitting robots to act more independently (Krouse, 1982: 52).

Finally, the third and fourth areas in which CAM technologies are applied, concerns the Process Planning and the Factory Management. On the one hand, material production usually implies the use of more than one tool and/or fabrication machine. On the other hand, the management of materials, facilities and products must be efficiently coordinated to optimize the industrial productive performance of the factory. Being complex analytical Just as an example of a CAM practice, for CNC milling a part, the operator has to provide a set

22

of information like machine type, fabrication operation, material parameters (e.g., size and position in the machine), tool(s) geometry (e.g., size and end shape), and machining parameters (e.g., milling depth, cutting and tool spindle speeds). Considering this information, the CAM software reads the geometry contained in the CAD model and writes the whole set of NC instructions necessary to drive the action of the milling machine. The sequence of the tool paths that are needed to mill a desired shape and texture is thus automatically generated, independently of the geometric complexity of the design.

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situations, computers can play a fundamental role in the planning and management of both situations by means of specific CAM systems. From the programming of the sequential procedures necessary for producing an element, to the overall virtual management of a factory, CAM systems comprises a wide range of specific software oriented to intervene in each of the areas mentioned above.

Although all these four areas of CAM technologies are meant to be used by experienced specialists, an increasing number of architects have become interested in the use of CAM systems during the last 15 years, not only as clients but also as users. Their goal is not, off course, to compete in the industrial production area, but to achieve a deeper sense of the emergent material possibilities that could enrich the conception and the execution of architectural projects. Occurring both at the practice and academic level, architect’s interest in CAD/CAM processes has been mainly centered in the first and second CAD/CAM areas, exploring digital fabrication and assembly processes. Indeed, an increasing number of architectural offices and architecture schools23 worldwide have incorporated digital fabrication equipment as part of their facilities. More recently, some schools like ETHZ in Switzerland, started also to explore the use of robots to perform assembly tasks oriented to building construction goals.

Considering the widely disseminated area of digital fabrication, it is possible to observe the commercial existence of: 

Independent CAM software to program several types of manufacturing instructions for different machines like MASTERCAM, SURFCAM, VisualMILL;



Integrated CAM applications within larger software packages like CATIA and TopSolid (TopCAM), but also in smaller applications like Rhinoceros (RhinoCAM).

In the beginning of this dissertation, it was not difficult to enumerate the schools around the

23

world that had digital fabrication equipment as part of their facilities. For instance, by 2003, there was no architecture school in Portugal that could offer such possibilities. Today, the scenario is radically different. To have digital fabrication equipment is becoming a norm in the schools in the United States and in many European countries. Considering this dissemination, is irrelevant to continuing enumerating the schools that have those technologies. As an example, during these last years, the IST‐UTL opened the first digital prototyping lab in Portugal and, since then, other architecture schools like FAUTL and U.M. have already followed its steps, while some others are on the way.

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Specific CAM applications supplied by machine manufacturers that are optimized for particular fabrication processes. For instance, Rapid Prototyping machines usually provide their own software to drive their fabrication operations.

During the PhD research, my practical experience with CAM technologies has been focused on the area of digital fabrication. In several academic and professional works, I had the opportunity to use CAM software (e.g., Visual Mill, RhinoCAM, TopCAM) to directly program operations like 2D laser cutting or 3‐axis milling [Fig. 3.20]. In others, I dealt with experienced operators who programmed for me, the CAM instructions for processes like CNC water‐jet cutting, CNC tube bending or CNC punching.

From these experiments, some of the benefits of using CAD/CAM systems became immediately clear. For instance, when looking into the NC code generated with a CAM software, it is easy to realize how hard could be for someone to manually program a fabrication operation. By comparing the task of programming the fabrication of a flat part with that of an irregular curved one, the time‐consuming difference to undertake both situations with CAM software is insignificant. On the contrary, by manually programming the NC code for the curved piece, if it is possible at all, it will take dramatically more time to be accomplished than the flat one. The perception of these situations at the manufacturing level is critical because they affect the formal possibilities for design exploration.

Figure 3.20 CAM programming for milling a part developed by the author for an assignment at MIT, 2003.

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This advantage introduced by CAM applications can yet be exponentially expressed if an architect wants to produce not one, but a set of parts with customized complex geometries. To manually write each specific fabrication instruction would be tremendously slow comparing to the use of computers.

In that context, certain geometric options could be easily discarded right in early design phases if one has to rely on non‐digitally driven manufacturing processes. The use of CAM software thus raises the potential to explore an expanded range of geometric possibilities, both at the formal and serial variational level, thereby enhancing designer’s creative possibilities.

Moreover, by sustain faster NC programming tasks, these technologies also introduces considerable cost benefits.

In addition to formal and cost advantages, the use of CAM software minimizes the possibilities for errors, and makes easier and faster the introduction of any change in the NC program. Simulating machining processes on the screen can give interesting feedbacks not only to optimize the fabrication process (i.e., by changing machining parameters), but also to realize some creative possibilities for exploring certain material effects that could not be anticipated before that experience (i.e., by playing with the tool geometry and tool paths parameters). Therefore, the close contact of architects with fabrication programming can be highly recommendable in some design situations.

Currently, an advanced trend in CAD/CAM processes in architecture consists in exploring computational design processes that associate the design geometry with their fabrication instructions. The goal, is to allow the exploration of some parametric design variations while the corresponding NC manufacturing instructions are updated in real‐time. On a first glance, automating this process could be uninteresting as it resembles conventional concerns with drafting automation. However, while the product of drafting is just a printed representation, the product of CAM instructions is a material object. By facilitating the generation of digital fabrication instructions throughout the design process, associative NC instructions encourages the making of material representations (e.g., physical models, prototypes and mockups), which can provide an invaluable feed‐back for the evolution of the design project.

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In the MORSlide project developed by ReD, the early production of physical prototypes was fundamental for calibrating the digital model definition with the resulting material expression [Fig. 3.21].

Figure 3.21 Morslide project by the author’ studio ReD. Showing the graphic pattern and the digital model (row above), Digital fabrication of prototypes for evaluation (middle row), and images of the completed work (row bellow).

This kind of practice to design and fabricate building components and assemblies has been explored with parametric design packages (i.e., TopSolid and TopCAM), and with algorithmic design techniques through computer programming (i.e., scripts that automatically generate 2D information for CNC cutting).

Despite the theoretical interest about this interactive link between CAD and CAM, there are some limitations, considering the bi‐directionality of the associative relationships. For instance, if a design system is defined in which variations of a design model produces automatically adaptations of the fabrication information, it is very hard to simultaneously set‐up the inverse

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associativity. Promising advanced conditions for the development of the architectural design, this problem about the information interactivity is definitely an interesting one24. It is widely discussed in Axel Kilian’s PhD research (2006), who also describes several practical experiments with different computational techniques that seek to sustain bi‐directional design environments.

3.3

MANUFACTURING TECHNOLOGIES

CAM software communicate with a landscape of computer‐driven manufacturing tools and machines that is in continuous expansion and diversification. Despite their versatility, these equipments do not have the same significance in the various disciplinary areas. As said in the introduction to this chapter, different disciplines tend to classify digital processes with different criteria and use them for different purposes.

In this context, this sub‐chapter covers current digital manufacturing technologies that are considered relevant for architecture today. As in the analysis of CAM software, the term manufacturing was used in the literature to describe the global enterprise that encompassed numerical control, robotics, process plan and factory management, this subchapter uses the same definition in general terms. Thus, technologies for manufacturing architecture are organized according to the three categories identified in following table [Figure 3.22].

Two of the most relevant consequences foreseen in bi‐directional design environments are

24

the encouragement and support of non‐linearity and concurrent multidisciplinarity the design process.

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Figure 3.22

Digital Manufacturing Technologies

Classification of the digital manufacturing processes

Digital Fabrication

3.3.1 Additive Fabrication 3.3.2 Subtractive Fabrication 3.3.3 Formative Fabrication

Digital Assembly

3.3.4 Robotic Assembly

Digital Construction

3.3.5 Additive Construction

The area of Digital Fabrication comprises the manufacturing of building components through additive, subtractive and formative processes, and then get their names from the nature of their actions over raw materials.

Accepting some simplification over the classifications proposed in other fields (e.g. mechanical engineering), this subdivision was introduced in studies conducted by architects like Volker R. Ruhl (1997: 69) or Branko Kolarevic (2000)25, and has been widely accepted and used in architecture since then.

The area of Digital Assembly consists in the use of robots to perform the assembly of building components like bricks.

The area of Digital Construction comprises computer‐driven machines that are currently under development aiming to fabricate not small building components but actual large building parts, or even the whole building.

In this context, Volker and Kolarevic’s proposal for the classification of digital fabrication processes are elaborated considering other useful references. Due to recent developments and interests, it seems justifiable the inclusion within digital manufacturing technologies of the areas of digital assembly and the

In mechanical engineering, Ibraim Zeid proposed a similar subdivision for manufacturing

25

processes (1991: 980‐983), considering “removing”, “forming”, “deforming” and “joining”. The main differences from this classification to the one proposed by Volker and Kolarevic resides in two aspects. Firstly, eventually due to the consolidation of rapid protoyping technologies, both architects considered the domain of additive fabrication including the formative and the joining processes. Secondly, assuming some simplification, Volker and Kolarevic integrated deforming processes within the “forming” ones.

used in architecture and construction.

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area of digital construction. The later is detached from the additive processes as it implies a totally different relation with the act of building, both conceptually and in scale.

3.3.1 Additive Fabrication

Additive digital fabrication processes are those involving “incremental forming by adding material in a layer­by­layer fashion, in a process which is the converse of milling” (Kolarevic, 2003: 36), and are also known as Solid Freeform or Layered Manufacturing. However, reflecting their original application oriented to the production of physical prototypes, these processes are commonly called as Rapid Prototyping (RP)26.

Additive technologies are a recent improvement in the field of fabrication, having emerged in the USA in 1987, with the commercialization of the Stereolithography system by the company 3D Systems. Because RP machines are small and they usually work with special materials, their main application has been the production of small models and tools. However, recent advancements in “materials, processing speed, accuracy and surface finish open an array of options that before were impossible” (Hopkins, Hague & Dickens, 2006: xvii), and permit the exploration of additive fabrication processes to directly produce final products in industries like product design.

In this context, Rapid Prototyping (RP) evolves into Rapid Manufacturing (RM), which is a recent but promising production trend. Supplanting the nature of prototypes and the constraints of tooling, RM is defined by Hopkison, Hague & Dickens (2006: 1) as “the use of computer aided design (CAD)­based automated additive manufacturing process to construct parts that are used directly as finished products or components”.

For instance, Nick Callicot (2001: 143‐149) uses Solid Freeform, Rob Thompson (2007: 232‐

26

241) comutes between Layered Manufacturing and Rapid Protoyping. F. Alves, F. Braga, M. Simao, R. Neto and T. Duarte (2001) centered their analysis around the term Rapid Protoyping.

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All additive fabrication processes read digital models from CAD files, usually in STL format, and cut its geometry in a sequence of very thin horizontal slices. This layered information is what drives the incremental addition of material and/or energy by the machine. Level by level, material is deposited and/or solidified, until the desired solid shape is completed. Because of the slicing processes, digital curved shapes are not really curved in reality.

However, the fabricated material layers are so thin (e.g., 0.01mmm) that in many techniques the stepped effect can remain undetectable in the end.

Recent improvements allow the fabrication of models with different colors and point out towards the possibility of producing models using different materials in one continuous process. Dealing with different materials and in different states, digital additive fabrication processes include the following technologies27 [Fig. 3.23]:

Figure 3.23

Additive Fabrication Processes

Classification of the additive fabrication processes

Liquid-Based Processes

Powder-Based Processes

Solid-Based Processes



Stereolitography (SLA) * **

according to Hopkinson,



Jetting Systems * ** (i.e Thermojet)

Hague and Dickens (2006),



Direct Light Processing



High-Viscosity Jetting



The Maple Process



Selective Laser Sintering (SLS) * **



Direct Metal Laser Sintering



Three-Dimensional Printing (3DP) * **



Fused Metal Deposition Systems



Electron Beam Melting (EBM)



Selective Laser Melting



Selective Masking Sintering (SMS)



Selective Inhibition Sintering (SIS)

with the identification of the TM

Technologies



Electrophotographic Layered Manufacturing (ELM)



High-Speed Sintering (HSS)



Fused Deposition Modeling (FDM) * **



Sheet Stacking Technologies * (i.e., Laminated Object Manufacturing / LOM)

* Processes that have been frequently regularly used for architectural applications. ** Processes experimented by the author.

A comprehensive list of RP and RM processes is provided and discussed by Neil Hopkinson

27

and Phill Dickens (Hopkinson, Hague & Dickens, 2006: 55‐79). However, the selected technologies are those that have been more consistently used in the architecture field.

most used ones in architecture.

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Compared to other fabrication processes, the additive ones offer some advantages like: 

Enabling the fabrication of forms with any kind of geometry.

Complex shapes with irregular curvatures, or solids with inside holes, are some forms that would be very hard or impossible to be materialized with any other process.



Affording the production of unique or small series of elements.

Although they are expensive processes, they can be cost competitive in these situations when compared to subtractive or tooling processes.



Fostering new ways of thinking the engineering design of elements in innovative ways. Products that are usually assemblies made out of several components can be rethought and simplified, considering fewer parts.



Facilitating the integration of fabrication technologies in a studio or office environment, due to the “clean” environment of additive processes.

Application in Architecture

In this context, while additive fabrication has the great potential to revolutionize some industries like product design, its potential to affect the discipline of architecture and the building industry is much more limited.

While, for instance, RP can be used by product designers to fabricate and test functional prototypes at 1:1 scale and, in some cases, using materials that are close or the same as the final one (e.g., like in RM), in architecture, the relationship between those manufactured products and their design objects ‐ buildings, is far more distant. The limited production size and the nature of their materials tend to relegate the use of additive fabrication processes to the production of scale models.

Valuable applications of Rapid Prototyping in architecture have been done essentially for evaluating the design geometry, especially if they have complex geometries. Using RP for thinking and testing the design’s constructability can be more problematic, due to a set of reasons like:

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The scale of an architecture model produced by RP is often so small that it forces to increase the digital models' thicknesses values to match the minimums required by those processes;



The materials used in RP are very different from the ones used in building construction;



Because the nature of additive processes has no parallel in existing building methods, the design and fabrication of additive models implies a different logic than those of real architectural design and construction.

Regarding the potential of Rapid Manufacturing in architecture, it can only be understood for the production of small‐scale components like structural connections and joints. However, its principles have inspired in the last years some researchers to develop specific additive manufacturing technologies to engage the scale of architectural buildings. However, because they occur in the construction site, they employ the final building materials and they aim to directly produce the final product at 1:1 scale –the building‐, it was decided to detach these efforts and initiatives from this group and discuss them in 3.3.5.

Experiments

Adding to a first experience with a Thermojet (3D Systems) in 2002, I developed a sequence of experiments to test other different additive fabrication processes. During the course of this research, I could explore FDM, SLS and SLA [Fig. 3.24 and 3.25], and 3DP [Fig. 3.26].

Figure 3.24 3D digital model of a Trifoil geometric shape (left).

Layered interpretation in the CAM software for FDM printing of a physical model.

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Figure 3.25

Additive fabrication models

of the Trifoil shape in FDM at

Eindhoven (center) and SLA

IST‐UTL (top), SLS at TU at FeyoDesign (bottom).

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From this different practical experiments, it becomes more clear some of the differences between those technologies



By extruding a melted plastic filament, FDM produces very strong models that permit the functional testing of assemblies and connecting systems. Fusing powder materials, like plastic, metal, polymers, ceramic or glass, through laser action, SLS is also a good process to produce resistant models. However, in some cases it can require the application of some finishing processes to improve its qualities. Through the solidification of liquid resins by laser, SLA processes also produce models with an acceptable physical resistance. On the contrary, produced by fine powder materials that are bonded layer by layer by an adhesive, 3DP models are extremely fragile and can be easily broken. Together with the Thermojet, the handling of these models is very limited.



Regarding the amount of post‐production needed to get the final model ready, Thermojet, SLA and FDM are technologies that create support, or secondary, structures to sustain the model during its fabrication. Once done, these structures have to be removed in a manual and time‐consuming fashion [Fig. 3.27]. In the case of the Thermojet, because the models produced are fragile, the removal of their support structures has to be done very gently. This situation represents thus a disadvantage when compared to 3D Printing and SLS technologies, which do not produce any supporting structure.

Figure 3.26 3D Printing: Model designed and fabricated at MIT.

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

Finally, SLA model presents a very good surface quality and fine details. However, it is a slow process involving some post‐ fabrication process, but the detail quality and precision of its

among these two processes.

As first concluding remark, the geometric freedom permitted by these additive fabrication processes is virtually unlimited and cannot be compared with any other manufacturing method. However, size is an important limitation, which is critical in architecture. To partially overcome this problem, design models can be subdivided in parts to be individually fabricated and assembled afterwards. However, while size constraints and material possibilities difficult the assessment of constructability concerns, the price of additive fabrication prevents from becoming a regular practice in both offices and academic institutions. The fact that architects are usually forced to adapt their digital models to fulfill thickness fabrication constraints, is also a less positive aspect of additive fabrication technologies.

Happening with some frequency, this fact clearly lustrates the fragile relation between the products of additive fabrication (i.e., models), and the products of architecture (i.e., buildings).

supporting structures of a FDM model.

models produced with the other technologies can be situated

Removing by hand the

production work. On the contrary, 3DP is a faster additive models is not so good. The geometric and finishing quality of the

Figure 3.27

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3.3.2 Subtractive Fabrication

Acting differently from the previous ones, subtractive fabrication technologies are those concerned with removing superfluous material from a solid material (i.e., a sheet or a block) to achieve a desired 2D and 3D shape.

These processes are old and were the first to incorporate the use of Computer Numerically Control technology, back in the fifties. For this reason, the terminology of CNC fabrication is usually associated with subtractive processes. However, since its incorporation in the first milling machines, CNC technology has spread over many other conventional fabrication processes.

The main applications of CNC subtractive fabrication are 2D contour cutting and machining, and 3D surface machining. In the first case, the machine cuts sheet type format materials following curves drawn in CAD files, or machines by turning axisymetrical parts. In the second case, the machine tool follows the paths generated directly from the surface(s) of a digital design model in order to progressively remove material from a solid block. In both scenarios, subtractive fabrication can work at multi‐scale production. Ranging from small machines to large‐size industrial ones, these processes are frequently used to produce 1:1 scale products in almost any kind of material, overcoming the size and material limitations of additive processes. However, it should be noticed that, when compared to additive ones, subtractive processes imply material wasting ‐ the leftovers from cutting or the removed material from machining ‐ as well as some manual labor to carry and position the raw material in the machine’s worktable, or bed. For these reasons, both aspects can have a critical impact on cost and time factors of subtractive fabrication.

When one tries to be more specific in classifying subtractive fabrication technologies, some ambiguity in terms of terminology emerges. The following comments unveil some aspects of this difficulty:



2D contour cutting processes are sometimes left out from the subtractive processes because there are some cutting processes that do not remove material when separating pieces out of a single material sheet (e.g., shearing, punching, blanking, laser‐cutting).

However, cutting with CNC milling implies the removal of material

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due to the thickness of both tools, describing a process usually known as chip forming. Also, when using water‐jet cutting, the abrasive jet has a thickness, which is derived from the diameter of the machine tool’s hole. Therefore, there is also some material removal in this widely used cutting process too. In this context, leaving cutting technologies out of subtractive processes could be incomplete, while its inclusion could be a bit imprecise.



Classifying fabrication operations according to the material format can be also problematic. For instance, CNC cutting processes, like laser cutting or water‐jet cutting, are usually associated with sheet‐ type materials. However, a CNC oxy‐fuel machine can cut a 10 inch thickness material, which can be considered as a block. Furthermore, CNC hot wire machines are very useful for cutting really large size foam blocks. In a different way, CNC milling is usually associated with the use of thick material blocks, but it can also be employed for cutting and engraving operations in very thin material sheets. Thus, subtractive processes enable working with very different materials formats.



Associating fabrication processes with 2D or with 3D operations can also be confusing. For instance, cutting processes are usually related with 2D contouring operations but in a CNC hot wire machine, it can occur in 3D movements. The same can happen with advanced 5‐axis laser‐cutting and 5‐axis water‐jet cutting. Also, depending on the programmed power of a CNC laser‐cut or the cutting depth of a CNC milling machine, an usual cutting operation can end up producing engraving effects without material separation .

In this context, this review opted to follow an inclusive classification of CNC subtractive processes, subdivided them according to the nature of their fabrication operations. The following table [Fig. 3.28] attempts to combine classifications proposed by Rhul (1997: 69), Lesko (1999: 5, 59, 69), Schodeck et al. (2005: 256‐268) and Kula & Ternaux (2009: 240‐243, 248‐ 251).

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Digital Subtractive Fabrication Processes Mechanical

Thermal

nonchip forming

chip forming

abrasive

Shearing

Boring

Grinding

Laser cutting

Punching

Trimming

Water-jet cutting

Plasma cutting

Blanking

Sawing

Abrasive-jet cutting

Oxy-Fuel Gas cutting

Ultrasonic machining

Hot Wire cutting

Electrochemical

Electrochemical Machining Photochemical Machining

Drilling Turning

Chemical Milling

Milling

Electrical Discharge Machining (EDM)

Routing

In the functioning of these processes, three situations can occur: 

the tool is fixed and the worktable moves;



the tool moves and the worktable stays fixed;



the tool moves and the worktable move simultaneously to increase machining flexibility and speed.

Also, there are some sophisticated machines that can be programmed to do more than one fabrication operation, including automatic tool changing and high speed‐machining capabilities. The most advanced are known as machining centers, when they include automatic tool change. In just a single set up, these machines can execute multiple fabrication operations in a continuous process that saves a lot of time.

Application in Architecture

In the field of architecture and building construction, subtractive fabrication processes are the most used digital manufacturing processes. Their application is mainly centered on: 

the direct production of final building components, like panels, masonry blocks, structural profiles, ornamental elements or furniture pieces;

Figure 3.28 Classification of digital subtractive classification processes.

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

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the indirect production of building components through the direct fabrication of specific molds.

Because of the production size and the type of materials that can be used, subtractive technologies are closer to the scale and materiality of architecture.

To point out some few examples, Kas Oostherhuis’ Web of the North Holland pavilion is an interesting construction where both covering panels and structural profiles were manufactured by CAD/CAM using 2D contour cutting processes. 3D subtractive fabrication processes were explored by Frank Gehry in the direct production of curved stone blocks for the Guggenheim Museum in Bilbao, but also for the indirect production of customized facade elements for the Zoolhoff Complex in Dusseldorf, through the CNC milling of individualized Styrofoam blocks to serve as molds for concrete casting [Fig. 3.29].

Figure 3.29

Kas Oosterhuis’ Web of North

Netherlands (top). Frank

Holand pavilion in the Gehry’s Zoolhof Complex in Dusseldorf (bottom).

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Experiments

During the PhD studies, the development of some practical tests and professional projects [Fig. 3.30] permitted contacting and testing several subtractive fabrication processes, involving different operations and materials.

The following tables resume this practical experience with the different degrees of personal involvement [Fig. 3.31, 3.32 and 3.33].

Figure 3.30 Selection of projects developed by ReD using subtractive fabrictaion processes.

5‐axis milling of molds for concrete in the XURRET System Project (left).

3‐axis surface milling of plywood panels in the MORSLide Project (center).

Texture engraving of acrylic panels in DRAGORAMA Project (right).

Figure 3.31

Direct Control of the Fabrication Process:

Subtractive fabrication technologies xhat were

Machine

Operations

Materials

MILLING

Contour cutting

Acrylic

3-axis milling

Cardboard

Engraving

Cork

directly programmed and operated by me, and the list

Styrofoam Wood BLADE CUTTING

Contour cutting

Paper Acetate

LASER CUTTING

WATER-JET CUTTING

Contour cutting

acrylic

Scoring

Cardboard

engraving

Cork

2d cutting

Glass Aluminum alloy

of materials that were used.

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Collaborations with Operators and Companies:

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Figure 3.32 Subtractive fabrication technologies that were

Machine

Operations

Materials

MILLING

5-axis milling

High density foam

MACHINING CENTER

3-axis milling

cork

PUNCHING

punching

Metal

programmed and operated by others, and the list of materials that were used.

Figure 3.33

Visits to Companies:

Subtractive fabrication technologies that were seen

Machine

Operations

Materials

SAWING

Contour cutting

stone

PLASMA CUTTING

Contour Cutting

metal

MILLING

3-axis milling

stone metal

LATHE

Turning

metal

From this experience and the analysis of the diverse landscape of CNC subtractive processes it is possible to draw some conclusions.

Firstly, by understanding that different machines can perform the same or similar fabrication operations, the selection of the most appropriated ones to perform a specific task may be carried by evaluating several parameters like:



Material properties e.g., in cutting, metal sheets are usually cut by laser or plasma cut, while glass panels are by water‐jet cut and wood by a milling or routing machine.



Design geometry e.g., in milling, complex design geometries can require the use of 5 axis milling machines in order to allow for under‐cut material removal. In cutting holes in a sheet metal, if they have all the same size, punching could be the most efficient process. However, if they have variable sizes, cutting them by laser or by punching machine could be the only available solution.

during visits to companies, and the list of materials that were used.

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

Desired fabrication effect e.g., by working with thick tools, milling operations can leave textures on the materials surface that can be interesting for an architect, and undesirable for a mechanical engineer. The machining parameters chosen are thus totally different and have consequences in the process cost and time.



Budget e.g., in milling, to match a certain budget, leaving visible some texture in the material can be accepted in order to reduce machining time, thus turning the fabrication process more cost‐effective.

Secondly, concerning the emergence of design opportunities, subtractive processes impose some constraints when compared to additive ones.

However, regarding traditional manual, mechanical or NC processes, CNC technology has dramatically expanded geometric freedom in fabrication.

Considering its particular nature and scale, architectural buildings imply the production of large quantities of components that must match construction budgets. In this scenario, CNC cutting processes allow for the fabrication of complex and variable shapes at an equivalent cost of that required for the production of simple and repetitive shapes, thus enabling the feasible implementation in practice of mass‐customization approaches. On the contrary, 3D subtractive fabrication, like milling or turning, requires long‐ time machining processes and produce a lot of wasting material, which has important cost and ecological implications. Milling a complex curved surface can take considerably more time than milling a flat one, which implies, therefore, a different cost. Thus, the promise of producing complex shapes with 3D subtractive processes is indeed technically possible today but, from the point of view of its feasibility, it constitutes a relative opportunity.

To overcome such limitations, architects tend to simplify their curved geometries by: 

rationalizing them into a set of flat building components that can be produced by CNC cutting processes;



by transforming doubly curved surfaces into developable ones, to enable the use of bendable materials (e.g., sheet metal)

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Being very frequently used, this production strategy reveals the gap that still persists between design intention and its physical manifestation. Despite all technological possibilities, crucial economic factors in fabrication still forces adopting design simplification –rationalization‐ options. However, if architects still want to produced smooth 3D curved surfaces, they tend to: 

mill cheap materials, like foam, to use them as molds (e.g., for producing concrete), or to use them as positive parts to be covered with rigid to materials like fiberglass or sprayed concrete



use stretchable materials, like textiles, which, despite their flexibility, they still imposes some design constraints and usage limitations.

Thirdly, by considering these manufacturing limitations, another conclusion focus on the emergent possibility for turning them into design opportunities.

For instance, in CNC milling, if the designers are closely involved with the fabrication processes, they can influence the selection of tools and their trajectories in order to accept and explore the emergence of textured effects left by the tool onto the materials’ surface. While reducing time and cost of the production process, such decisions can yield interesting and original visual and tactile qualities of the final products. In other situations, the necessity to rationalize curved surfaces into faceted ones can launch the opportunity for exploring emergent structural grids, paneling patterns and joint effects that were not considered before.

Finally, due to their multi‐scalar and the possibility of using many different and easily available materials, including those used in building construction, CNC subtractive fabrication processes encourage the production of not only final building components but also prototypes and mock‐ups throughout the design process. The experience of 1:1 scale models and/or final building parts can give invaluable feed‐back to the architect leading him to test and develop his design in novel ways, thus suggesting both eventual corrections or new opportunities.

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3.3.3 Formative

Differently from the previous ones, formative processes neither add nor subtract material. Instead, “mechanical forces, restricting forms, heat or steam are applied to a material so as to form it into the desired shape through reshaping or deformation” (Kolarevic, 2003: 38). In their traditional form (non‐digital), formative fabrication processes have been widely employed over time and include a wide range of deforming, molding and casting technologies. Its versatility and relevance is demonstrated by the possibility of its application to all types of materials.

As discussed by Ruhl (1997: 73), the nature of formative fabrication is difficult to automate. In fact, only in a few processes has CNC technology been directly incorporated to command their operation. For instance, some mechanical deformation technologies involving bending and folding operations with metal sheets and tubes can be performed by digitally‐driven machines. However, a wide range of traditional manufacturing processes have benefited from digital fabrication technologies in a indirect way. Many formative processes involving patterns or molds, like stamping or casting techniques, can find an expansion of their applications through the digital production of their tools and molds. Using CNC additive and subtractive fabrication, “the ease with which this [the production of molds directly from 3D CAD files] can be done, relative to traditional pattern and mold making, has allowed for the design of products using fewer, more complex parts at lower cost” (Schodeck et al. 2005: 243). Moreover, after some formative processes, CNC subtractive fabrication can be again employed to correct the final shape of the parts. For this reason, the global impact of digital fabrication technologies on formative fabrication should not be disregarded.

The diversity of technologies available and the different ways in which they have benefited from digital technologies, makes difficult to establish a definitive classification of formative processes. While Rhul (1997: 74) attempts to identify only the few that are digitally controlled, thereby dividing them in “mechanical deforming” and “thermal deforming”, Shodeck et al. (2005: 268‐284) also includes those that are indirectly digitally enhanced, dividing the processes in “deformation and molding” and “casting”. Aligned with this general overview, and following criteria similar to

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those used in additive processes, Lesko (1999: 5) classifies formative processes according to the state of the raw material, providing independent reviews for metals (24‐57) and plastics (resins) (140‐167), and some special considerations for ceramics (196‐198) and glass (200‐204).

Because, there are opportunities for affecting traditional formative processes through CNC fabrication, even if only indirectly, it seems useful to make a general review of all processes, following Shodecks and Lesko’s own reviews.

Figure 3.34

In a similar way to additive ones, the following table attempts to combine

Formative fabrication

Lesko’s categories with Shodeck’s review, as well as other additional

processes benefiting from digital technologies.

references [Fig. 3.34].

Formative Fabrication Liquid State METALS

Expendable molds:  Sand casting  Full mold casting (evaporative pattern casting)  Investment casting (lost wax, precision casting, solid mold)  Plaster molds  Ceramic shell casting  Ceramic molds

Plastic State Forging  Hammer  Drop forge  Press forging  Upset forging  Rotary Swaging Rolling  Cold rolling  Hot rolling Drawn Wire

Nonexpendable molds:  Graphite molds  Permanent molds (metals)  Low-pressure casting  Vacuum (die) Casting  Die casting molds (steel)  Spin and centrifugal casting  Continuous casting  Metal injection molding PLASTICS

        

Casting Contact molding BMC Molding Reaction Injection Molding Compression Molding Transfer Molding Rotational Molding Injection Molding Extrusion

Extrusion  Direct extrusion  Impact extrusion

Solid State Simple Bend  Wire bending and forming  Tube bending  Sheet-metal bending  Roll bending and forming  Air and V-Die bending  Stretch forming  Laser beam Compound form  Spinning  Hydro forming  Drawing and deep drawing  Peen forming  Explosive forming  Coining Form and Cut  Stamping

 Expanded Bead Molding  Thermoforming (vaccum-forming, pressure-forming)  Blow Molding

     

Bending Coining Forging Extrusion Rolling Drawing

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Besides the materials presented on this table, other materials, like some wooden products or modern composites (e.g., Corian) can also be formed through some of the described processes, like thermo‐forming.

Despite their versatility, formative processes present some limitations. The production of forming tools, like molds, tend to be a very complex and expensive process that offers no flexibility in the end. For this reason, the exploration of formative processes tends to encourage mass production practices based on standardization. Finding a way to overcome this limitation has been a critical challenge as it holds the great potential to affect the design level. In practice, CNC fabrication coupled with cheap molding materials for the fabrication of forming tools has been explored as a strategy for facilitating the production of smaller series. Simultaneously, the idea of developing flexible molds is one that has been insistently pursued at the research level. At its basis there is the desire to sustain a high level of customization, through the possibility for reconfiguration, and achieve a high degree of precision, through the capacity to be automated.

One of the most widely explored concepts consists in a flexible mold based on a matrix of physical pins with individually movement capacities controlled by CNC technology. In this system, three‐dimensional surfaces designed in CAD files can automatically activate that matrix to reproduce its geometry. The physical surface described by the pins can thus be used as a mold for several formative processes, like casting, thermo‐forming, pressure‐ forming or vacuum‐forming. With automatic reconfiguration possibilities, a single mold can be used to fabricate geometrically distinct elements. Inspired

by XX century precedents28, one of the current advancements following this concept is the FlexiMold developed by the mechanical engineer Sebastiaan Boers at the Technical University of Eindhoven [Fig. 3.35]. Working with prototypes with two different sizes, he has been directing his technology to the market of product design and building construction.

Acknowledging the fact that flexible molds are not new ideas, Sebastian Boers mentions

28

precedent works as inspirations for his own research: a forming device for automobile leaf springs developed by Williams and Skinner in 1923, A process and apparatus for manufacturing anatomically accurate individual foot support for shoes developed by Fritz Hess in 1931, and an automatically reconfigurable mold for jet fighters developed by Northrop Grumman and MIT, which is commercially used for stretch forming. Pin art design toys from the 1980’s were also a major inspiration for Boer’s FlexiMold.

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Figure 3.35 FlexiMold prototype by Sebastiaan Boers.

Applications in Architecture

Since the antiquity, different formative processes have been employed for the production of building components, structural parts or decorative elements. Throughout the history of architecture, deforming, molding and casting techniques have been widely explored to craft customized building components or to mass produce standard ones, in materials like metals, glass or concrete.

In the recent years, perceiving the potential of digital technologies to promote geometric freedom, architects have been increasingly interested in exploring the use of CNC technologies to both direct and indirectly augment formative fabrication possibilities to fulfill design expectations.

Designed by Bernard Franken for the Salon d’Automobile in Geneva (2000), the “Wave” Pavilion project is an example of the use of CNC formative processes. The double‐curved surface of this pavilion was materialized by using the iso‐parametric lines of the digital model’s wireframe to inform the CNC bending of aluminum tubes. This integrated digital design and fabrication process was thus the decisive factor to make possible the fabrication of the unique 3D curvature of each structural profile. [Fig. 3.36]

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Figure 3.36 The Wave Pavilion project by Bernard Franken.

Taking advantage of the digital indirect influence on formative fabrication, it is possible to find plenty of examples involving casting or deforming processes.

The CNC milling of Styrofoam blocks to produce customized formworks for concrete casting, has been explored by several architects. Frank Gehry in the Zoolhof Towers in Dusseldorf (2000) or, more recently, Zaha Hadid in the Phaeno Building in Wolfsburg (2005), have used this technique to assure the materialization of the curved surfaces of their designs. For the concrete structure of Villa Nurbs in Ampuria Brava, Enric Ruiz Geli opted to CNC mill several layers of wood to use on‐site as formwork. A similar technique, involving heat‐deformation, has been explored to fabricate custom glass and acrylic panels, like in Bernard Franken BMW “Bubble” Pavilion in Frankfurt (1999), Frank Gehry’s Conde Naste Cafeteria in New York (2000) or in Peter Cook and Colin Fournier’s Kunsthaus Graz museum (2003). In a different way, exploring mechanical deformation, Herzog and de Meuron’s project for the Walker Art Museum in Minnesota (2005), involved the CNC fabrication of custom patterns for stamping aluminum anodized panels with an original 3D texture to cover the exterior facade [Fig. 3.37].

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Figure 3.37 Herzog & de Meuron Walk Art Center project, with the facade covered by shaped aluminum panels.

As said before, formative processes are difficult to be automated as they require a deep knowledge of material’s properties and behaviors to handle with the imprecision that is inherent to the material states and processes involved. Even if they can be indirectly digitally enhanced, formative processes still very much rely on traditional craft skills, analog processes and important material tolerances. This is clear on Michael Samra’s observation, about TryPirmid’s experience in the forming fabrication of customized architectural components: “even though we rely heavily on digital technologies in the design process up to this point, once we get into the casting world it becomes a black art. We deal with physical materials that are gated up onto wax structure and dipped into a refractory plaster. The wax is then burned out, and then parts are cast by pouring molten metal in the plaster mould. This analog process is, in many ways, the complete opposite of CAD/CAM technology.” (Bechthold et al. 2003: 16)

For this reason, and differently from additive and subtractive technologies, it is rare to find formative fabrication equipment in architectural schools and offices. Collaboration with skilled fabricators is a decisive factor for the success.

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Experiments

During the PhD research I had some opportunities to work with formative fabrication processes, which emerged out of experiments in professional design projects and visits to specialized companies.

In the studio ReD, we did two projects involving the use of CNC formative processes. In 2005, we designed a six suspended cone‐shape volumes to show video projections in their interior. To fabricate the cone’s structural rings, Procedes company in Bremen took our digital files to inform the CNC bending of aluminum tubes. Although the ring’s radius were constant, this digital process still revealed to be more convenient to accomplish the job [Fig. 3.39]. More recently, we have done in 2007‐08 a research project with IMAR company from Bilbao where new applications for perforated sheet metal were investigated. Paying a special attention on the development of three‐dimensional structures with folded sheet‐metal components, some prototypes were produced using IMAR’s CNC press‐brake.

In some visits to industrial companies and buildings, I had the opportunity to see vacuum forming processes of corian and plywood using CNC milled

Figure 3.38 CONEplex installation in the Kunsthaus Graz designed by

molds in the catalan company Industria de la Fusta Vila, where parts for Toyo

ReD. The aluminum tubular

Ito’s and Zaha Hadid’s buildings were being produced [Fig. 3.39]. In a visit to

rings were CNC bended.

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the Villa Nurbs housing project by Enric Ruiz Gelli / Cloud 9 in Ampuria Brava, it was possible to see and know about the customized ceramic and glass panels that were formed from CNC milled fabricated molds.

From this experience, the world of formative fabrication reveals to be as interesting and stimulating as it is complex. The need to collaborate and involving trained fabricators in the design process is decisive. The myriad of available fabrication techniques and the complex world of material properties and behavior makes very difficult for architects to define the correct fabrication strategy for achieving accurate results and economically feasibility.

3.3.4 Robotic Assembly

In pair with the fabrication processes, there are digital technologies to assist assembly of the parts to achieve composite elements and structures.

Requiring precise orientation and motion in space, these processes are usually carried by robotic equipment, which can perform multiple tasks directly instructed by computers. In the factory, as explained by Krouse (1982: 52), robotic arms are versatile machines that can be used to: 

select and position tools and workpieces for NC machine tools;



carry equipment or parts between vary locations on the shop floor;



to grasp and operate drills, welders, and other tools.

Thus, this category of digital manufacturing technologies correspond to the second area of CAM applications29.

See 3.2.3 of this dissertation.

29

Figure 3.39 Visit to the manufacturing company Industria de La Fusta Vila, near Barcelona.

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Applications in Architecture

Involving the negotiation between prefabrication and on‐site construction, architecture buildings consist in large‐scale assemblies that are done by hand with the help of tools and machinery. In the analogical condition that have ruled the assembly processes there is a window of opportunity for improvement. To explore it, the application of digital processes have occurred in two, complementary, ways: indirectly, by expanding traditional methods, or directly, by substituting them. In any case, the underlying motifs can be focused on productivity and quality goals, but also on uncovering aesthetics and tectonic opportunities. Following there is a description of three different examples that present different degrees of digital technology application.

Starting from an indirect influence scenario, Branko Kolarevic launched the digital field of “assembly” in his essay (2001), by pointing out a set of computer‐driven technologies used at the construction site to help the workers implanting the future building in space, and to determine the precise location of its material components. This digital assistance is particularly relevant when buildings have complex shapes, which are difficult to position in the real space, or when its construction integrates non‐ standard components, which imply a specific and precise position for each of them. In both cases, digital CAD files are used to instruct electronic surveying and laser positioning systems to guide in space the physical construction evolution. Thus, as explained by Kolarevic, “after the components are digitally fabricated, their assembly on site can be augmented with digital technology”.

Buildings like the Guggenheim Museum in Bilbao wouldn’t be possibly if there weren’t these digital systems. Nonetheless, despite the digital interference, the assembly construction process still continues to be a fully hand‐made process.

An advancement of this condition have been explored since the 1980’s in the United States and in Japan, trying to increase the degree of automation at the construction site. In their 1998 book “Construction Robots”, Leslie Cousineau and Nobuyasu Miura present several automated systems developed to integrate automated forces in the assembly processes, revealing the leading initiative of Japan in the field. Principles of Computer Integrated manufacturing (CIM) processes are at the basis of what is called in this book

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as Computer Integrated Construction (CIC). The first application of this concept to a full‐scale building happened in 1991 in Nagoya. Then, the SMART System (Shimizu Manufacturing system by Advancing Robotics Technology) was used to construct the 20‐story height building for the Juroku Bank [Fig. 3.40]. Consisting in five technologies, “an automated lift­up system, an automated transport system, a steel assembly system, an automated welding system, and a computerized information management system”, the use of the SMART system automated the “erection and welding of the steel frame

Figure 3.34

structure, placing of concrete floor panels, and installation of exterior and

SMART System by Shimizo

interior wall panels”. Besides these aspects, the rest of the construction required conventional construction methods. In a short analysis to these on‐ site construction robotic practices, two remarks should be highlighted: that buildings are still accomplished involving a large portion of human intervention, and that the success of CIC depends on the degree of repetition in building design and construction30. Although productivity and quality construction goals seems to prevail facing design interests, that performance in some of the CIC systems described in the book are evaluated as not fully satisfactory.

Working more at the prefabrication level, but involving full automation of the assembly process, architects Fabio Gramazio and Matthias Kohler have been investigating at the Zurich’s Federal Institute of Technology (ETHZ) the use of a robotic arm to explore emergent architectural opportunities. While this technology is widely spread in the manufacturing industries to increase productivity and sustain mass‐production practices, Gramazio+Kohler envisioned the potential of robots to address alternative production possibilities. In their practice, “instead of repetitively stamping, cutting, welding, or moving, the robot performs multiple and varied tasks to create highly unique and carefully crafted objects” (49, 50). Besides the use of their KR150 L110 robot to perform subtractive fabrication operations, Gramazio + Kohler have explored in several projects its potential to produce material assemblies with variable geometries directly from computer data. For instance, with their “Resolution Wall” project (2007) they have demonstrated that, unlike human action, assembling different size components doesn’t affect the working performance of a robot. In their words: “the time needed by the robot to put in place a module like this is The authors explain that “the greater the degree of repetition, the more incentive there is to

30

integrate single‐task robots”.

employed in the construction of a tower.

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independent of its size, because the required movement path remains the same” (2008: 64). With a different starting point, the “Domoterra Lounge” project (2007) used a standard and conventional material –the ceramic brick‐ to create variable assemblies describing non‐regular geometries. Developing algorithmic design approaches, the individual position and rotation of over 400 bricks was digitally defined enabling the robot to assemble each one of them “in a different way without optical reference or measurement, i.e. without extra effort” (2008: 62). This idea of “programmed walls” was tested in larger projects like the Gantenbein Vineyard Facade in Flasch (2006) [Fig.3.41] or the “Structural Oscillations” installation for the Swiss representation at the 11th Venice Architecture Biennale (2008).

The three examples described before illustrated current digital technologies that contribute to augment the possibilities for architectural constructions

Figure 3.41 The use of a robot for assembling a brick facade

based on material assemblies. While the first and third cases seem to operate

part in Gramazio & Kohler’s

supporting creative design approaches, the second case seems to base its

Gantenbein Vineyard project.

operative potential on design rationalization efforts.

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3.3.5 Additive Construction

Considering the particular scale of architecture buildings, there are some recent research initiatives towards the development of specific CNC manufacturing technologies oriented for the building construction industry.

Instead of adopting existing commercial equipments, originally developed for other industries, like in the previous examples, leading researchers have been focusing on creating new machinery to tackle the complexity and the scale of architectural buildings. Their main goal concerns the CNC construction of 1:1 scale buildings following an additive approach inspired by rapid prototyping/manufacturing technologies.

Although one could tend to integrate these processes within the “additive fabrication” category, they present some important conceptual differences that seem to justify the emergence of an “additive construction” category. By only enabling the production of small models, additive fabrication technologies sustain a clear gap between its manufactured products and architectural buildings. Even in the rare cases where small scale building components can be directly or indirectly produced by rapid manufacturing, a critical scale distance between them and architectural buildings still exist. In these situations, besides its metric dimension, that distance is also a conceptual one because, for instance, the size limitations of additive fabrication technologies forces the understanding of buildings as an assembly of parts, like in subtractive and formative processes. In this context, additive construction is not about the fabrication of components in the shop to be used to construct buildings afterwards, but, actually, it is about the possibility for the construction of the building itself, directly on‐site.

In this fashion, buildings’ form and structure become the result of a continuous material deposition process guided by 3D CAD files, which ultimately can conceptually blur the notion of assembly. This idea is not really new, as it can find resemblances in traditional construction methods.

Based on a liquid material, concrete technology has been seen from its beginning as capable to produce free‐form and continuous building structures. Thomas Edison was one of the first to imagine this possibility that is today supporting the construction of buildings with complex geometries.

However, its formal and scale potentials are strongly limited by material and

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size constraints of the formwork. It is precisely the notion of such limitations that specialists have been trying to overcome through the development of specific CNC additive construction technologies that promise to tie design freedom with fast, flexible, precise, safe and clean construction processes.

Applications in Architecture

In the research context of digital additive construction technologies, it is possible to highlight three main initiatives:



Contour Crafting (CC) Developed by Behrokh Khoshnevis at the University of Southern California, Contour Crafting (CC) technology is an additive ‐layer‐by‐ layer‐ construction process that works at the scale of architectural buildings, automating its construction31. Visually similar to the bridge of a CNC milling machine, CC proposes the on‐site installation of a huge gantry system carrying a nozzle, with two adjacent trowels.

Exploring computer control, the gantry combines XYZ movements, the nozzle can rotate till 6‐axis, and the trowels can deflect to allow the construction of non‐orthogonal shapes. Technically, the process unfolds in two steps: first the CC machine builds the outer surfaces of the structures through material extrusion, and then it fills the inside by pouring or injecting a core material. According to Khoshnevis, “using this process, a single house or a colony of houses, each with possibly a different design, may be automatically constructed in a single run, embedded in each house all the conduits for electrical, plumbing and air­conditioning” (Khoshnevis, 2004).

The field of CC applications is extensive, ranging from the fast construction of houses for emergency scenarios or extraterrestrial applications for building habitats in Moon and Mars. At the moment, after the development of several CC machines for research and fabrication with several materials. In the near future, Khoshnevis plans to manufacture full scale sections of buildings. Simultaneously,

The research on Contour Crafting has been widely divulged in scientific papers, general press

31

and tv shows. This technology also counts with a specific website containing text, images and video information, which could be visited on April 2009 at: http://www.contourcrafting.org.

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there are studies being conducted to develop an alternative approach based on the use of robots to perform the CC operations on‐site. [Fig. 3.42]

Figure 3.42

Contour Crafting technology.



FreeFrom Construction/Engineering UK Sharing very similar concerns and hopes, researchers at Loughborough University in UK have been exploring layering fabrication technologies to produce freeform architectural constructions32. Headed by Rupert Soar, a mechanical engineer, the FreeForm Construction group has been exploring their expertise on rapid manufacturing processes to scale them up in order to enable building constructions out of material deposition processes. In their words, their goal consist in “print full‐scale wall and volumetric components, layer by layer, freeing the constrains of straight line form and allowing full systems integration”33. Some of the main inspirations of Rupert Soar’s investigations comes from observations of the natural world. Termite mounds and human bone are fertile ground for biomimetic applications for the development of flexible manufacturing processes and new material concepts.

The FreeForm construction research headed by Rupert Soar hás a website called “FreeForm

32

Engineering” that could be consulted on April 2009 at: http://www.freeformconstruction.co.uk or at http://www.freeformengineering.co.uk Extracted from the website at the Loughborough University of the Freeform construction

33

research Project, consulted on April 2009 at: http://www.lboro.ac.uk/departments/mm/research/rapid­ manufacturing/projects/mega_scale_RM.html

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D_Shape Following the same construction concept as the previous examples, D_Shape is a technology that has been developed by Enrico Dini, a civil engineer with an extensive experience in the mechanics, automation and robotics sector34. Previously called Monolite, this invention departs from the freeform fabrication possibilities offered by sterelitography processes to envision its application at the scale of architectural buildings. For Enrico Dini, the only conditions that are necessary to achieve this goal is the design and construction of a machine of adequate size and the use an efficient binder. The D_Shape technology has been tested in practice with a full‐scale protoype with 6mx6m. A light aluminum structure carries a computer driven printing head that deposits sand with a special binder, layer by layer. Exhibiting a complex geometry with 2 meters height, the Radiolaria project became the first built example, and took about 2 weeks of production, and 1 week of finishing by hand. After this laboratory machine experience, Dini is now aiming to build a printer for the construction site that is user‐friendly, modular and capable to use local sands to reduce environmental impacts. [Fig. 3.43]

Figure 3.43 D_Shape free additive construction technology.

D_Shape technology has a dedicated website that could be consulted on April 2009 at:

34

http://www.d­shape.com.

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CONCLUSION

This chapter provided a review of the set of digital technologies that are used for design and manufacturing in architecture. Besides the explanation of the concepts and principles inherent to the available solutions, it presented some personal experiments that allowed me testing the potentials and limitations of many of the mentioned technologies. Following this combined methodology, some specific reflections, or conclusions, were provided for each analyzed topic. Thus, in order to avoid repeating them, some of the most relevant are following highlighted:



The range of digital technologies that can be employed on architecture is not disciplinary defined. Indeed, interesting technologies and processes (i.e., parametric design, CAD/CAM or CNC fabrication) have been found in adjacent design areas, like mechanical engineering. Therefore, architects will necessarily continue looking into other fields in the search for technology transfer opportunities that could not only solve existing problems, but also stimulate disciplinary invention and/or innovation.



Besides this external trade and influence, specific architectural research on digital technologies have increased during the last decade. Alternative CAD strategies based on computational power have been developed under architects’ orientation to pursue specific disciplinary goals (i.e., scripting processes and software like Generative

Components,

Digital

Project

or

Grasshoppers).

Demonstrating a wider commitment of the discipline to play a role in the technological developments, some digital manufacturing technologies started to be explored and even developed to fit the specifics of building construction activities (i.e., the investigation of robotic assembly processes or the researches on additive construction technologies).



From the point of view of creativity, computational design processes enable the combination of representation and calculation capabilities to sustain novel design experiences that could not be offered by any other analog or digital process. In this context, the

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exploration of parametric and algorithmic strategies, either by programming or by software approach, can trigger the conceptual reasoning processes that usually occur in human’s mind: The digital emerges thus as a creative environment that supports a collaborative design trade between the architect and the computer.



Although some digital packages tend to suggest inclusive environments to perform the whole set of design tasks, that difficulty could happen in architecture. The complexity of its practice characterized by heterogeneous conditions like, for instance, the intervention in diverse cultural and technological contexts, the negotiation of information with a wide range of specialists that relying on different technologies, and the intricacy and scale of its products (buildings), forces architects to master the combination between available technologies to provide successful answers for each situation.



Currently, CAD technologies offer design tools to represent and analyze any imaginable geometry. Leaving aside some economical constraints, it could be also argued that it is possible to find a CAM strategy to enable the materialization of any digitally represented form. However, the successful exploration of the most extreme possibilities of this geometric freedom implies the integrated use of both technologies. In other words, it doesn’t matter if it is easy to design a complex shape in the computer if a solution for its materialization it’s not provided. In the other way, it doesn’t matter to know that any shape can be fabricated if the selected design processes are limitative of the designer’s geometric representation possibilities. Master the integration of efficient CAD and CAM technologies is a condition to explore the augmented space of design possibilities.



The use of digital design, engineering and manufacturing technologies brings together a set of design promises like: achieving a higher levels of precision, enabling the production of more geometric possibilities and the affordance of mass customization practices. Although conceptually these three promises seem to be valid, in the reality of architecture, their effectiveness is actually relative, mainly due to economic constraints. Representation

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technique, element’s geometry, material properties and fabrication process are some of the parameters that must be carefully orchestrated to define a feasible CAD/CAM process that is efficient in matching the original design intentions. In many situations, it is not yet possible to find convenient solutions for the variables of that equation, which force architects to develop design rationalization efforts to find a new set of factors that could sustain feasibility.



Differently from industrial design, where their products tend to be small and made out of few parts, few materials and few manufacturing processes, architectural buildings are complex and big‐size objects that involve the selection and assembly of a wide range of materials and structures. Therefore, building construction necessarily implies the combination of many manufacturing technologies. Architect’s interest on CAM processes may thus encompass the whole family, concerning additive, subtractive, formative or robotic processes, to formulate the appropriate strategies to produce prototypes, physical mock‐ups and the building components.



Differently from automotive or aerospace industries, the design of a building is usually unique and not one intended to be mass‐ produced. Therefore, the economical investment and return behind the production of a car or an aircraft is incomparable superior than the one available in the production of a building. Thus, the possibility to rely on automated manufacturing processes is far more limited in building construction, which, one more time, can force architects to define intelligent solutions that combine digital processes with conventional or traditional ones.



Finally, a last consideration to highlight that despite the original goals of each technology, there is always a creative space for exploration to take the most out of it. In other words, it seems reductive thinking that there is a single way or purpose attached to each specific technology. In fact, the deepest the knowledge about them is, the better conditions exist to uncover novel design and material opportunities.

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Summarized in the previous set of observations and verifying the spreading tendency for its adoption, the opportunities launched by current digital technologies for the design and manufacturing motivates questioning its influence in the practice of architecture. The next chapter is thus dedicated to investigate the consequent methodological implications, the emergent interests in contemporary architecture, and the impact on its materiality..

3.5

REFERENCES

References that are not mentioned in this chapter’s text belong to the credits of the images used, and are cited in the “Illustration Credits” section of this thesis.

(1)

Alves, F., Braga, F., Simão, M., Neto, R. & Duarte, T. (2001): Prototipagem Rápida, Protoclick.

(2)

Brauer, J.R. (1988): What Every Engineer Should Know About Finite Element Analysis., Marcel Dekker, New York.

(3)

Bechthold, M. (2001): Complex Shapes in Wood. Computer­Aided Design and Manufacture of Wood­Sandwich Roff Shells, Doctor of Design Dissertation, Graduate School of Design, Harvard University, Cambridge MA.

(4)

Bechthold, M.; Griggs, K; Schodeck, D. & Steinberg, M. (Eds.) (2003): New Technologies in Architecture II & III. Computer Aided Design and Manufacturing Techniques, Harvard Design School, Cambridge MA.

(5)

Boer, S. & Oosterhuis, K.: “Architectural Parametric Design and Mass Customization”, Paper presented for download in the studio’s office website: http://www.oosterhuis.nl

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(6)

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Brauer, J.R. (Ed.) (1988): What Every Engineer Should Know About Finite Element Analysis, Marcel Dekker, New York NY.

(7)

Burry, M. (1997): “Computer Aided Architectural Design Using Parametric Variation and Associative Geometry” in Proceedings of the 15th eCAADe Conference, Vienna University of Technology.

(8)

Burry, M. (2003): “Modernisme, Modernism and Third Millenium Praxis”, in dECOi Architiect(e)s Exhibition Catalogue, FRAC, Orleans.

(9)

Caldas, L.G. (2001): An Evolution­Based Generative Design System: Using Adaptation to Shape Architetural Form, PhD Dissertation in Architecture, Design and Computation, Massachusetts Institute of Technology, Cambridge MA.

(10) Callicott, N. (2001): Computer­Aided Manufacture in Architecture.

The Pursuit of Novelty, Architectural Press, Oxford.

(11) Chaszar, A. (Ed.) (2006): Blurring the Lines, Wiley‐Academy, West Sussex UK. (12) Cook, R.D. (1981): Concepts and Applications of Finite Element Analysis, John Wiley & Sons, New York.

(13) Cousineau, L & Miura, N. (1998): Construction Robots. The Search for New Building Technology in Japan, ASCE Press.

(14) Desai, C.S. & Abel, J.F. (1972): Introduction to the Finite Element Method. A Numerical Method for Engineering Analysis, Van Nostrand Reinhold Company, New York NY. (15) Duarte, J.P. (2001): Customizing Mass Housing, PhD Dissertation in Architecture, Design and Computation, Massachusetts Institute of Technology, Cambridge MA. (16) Fernandéz­Galiano, L. (ed.) (2005): Herzog & de Meuron, AV n.114, July‐August, Madrid.

(17) Furtado, R.; Oliveira, R. & Moás, P. (2005): “Casa da Música, Porto”, Structure Engineering International 2/2005.

(18) Gramazio, F. & Kohler, M. (2008): Digital Materiality, Lars Muller Publishers, Basel.

(19) Hopkinson, N., Hague, R.J.M. & Dickens, P.M. (2006): Rapid Manufacturing. An Industrial Revolution For The Digital Age, John Wiley & Sons, West Sussex UK.

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(20) Kalay, Y.E. (2004): Architecture’s New Media, MIT Press, Cambridge MA. (21) Khoshnevis, B. (2004): “Automated Construction by Contour Crafting – Related Robotics and Information Technologies”, in Journal of Automation in Construction – Special Issue: The best of ISARC 2002 (pp. 5‐19), Vol.13, Issue 1, January.

(22) Kilian, A. (2006): Design Exploration through Bidirectional Modeling Constraints, PhD Dissertation in Architecture, Design and Computation, Massachusetts Institute of Technology, Cambridge MA. (23) Kolarevic, B. (2000): “Digital Architectures”, in M Clayton and G.P. Vasquez de Velasco (Eds), Eternity, Infinity and Virtuality in Architecture, Proceedings of the ACADIA 2000 Conference, pp. 251‐ 256, Washington DC. (24) Kolarevic, B. (Ed.) (2001): “Digital Fabrication: Manufacturing Architecture in the Information Age”, in W. Jabi (Ed.), Reinventing the Discourse, Proceedings of the ACADIA 2001 Conference, pp. 268‐277, Washington DC. (25) Kolarevic, B. (Ed.) (2003): Architecture in the Digital Age. Design and Manufacturing, Spon Press, New York NY. (26) Kolarevic, B.; Malkawi, A.M. (Eds.) (2005): Performative Archiitecture. Beyond Instrumentality., Spon Press, New York NY. (27) Kolarevic, B. & Klinger, K. (Eds) (2008): Manufacturing Material Effects. Rethinking Design and Manufacturing in Architecture, Routlege, New York.

(28) Krouse, J.K. (1982): What Every Engineer Should Know About Computer­Aided Design and Computer­Aided Manufacturing. The CAD/CAM Revolution., Marcel Dekker, New York NY. (29) Kula, D. & Élodie, T. (2009): Materiology. The Creative’s Guide to Materials and Technologies, Birckhauser, Basel.

(30) Lee, K. (1999): Principles of CAD/CAM/CAE Systems, Addison Wesley Longman, (31) Lefteri, C. (2007): Making It. Manufacturing Techniques for Product Design, Laurence King Publishing, London.

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(32) Lesko, J. (1999): Industrial Design and Manufacturing, John Wiley & Sons, USA. (33) Loukissas, Y. (2003): Rulebuilding. Exploring Design Worlds through End­User Programming, Master of Sience in Architecture Studies Thesis, Massachusetts Institute of Technology, Cambridge, MA. (34) Machover, C. & Blauth, R.E. (Eds.) (1980): The CAD/CAM Handbook, Computervision corporation, Bedford MA. (35) Malé­Alemany, M. & Sousa, J.P. (2003): “Parametric Design as a Technique of Convergence”, in Proceedings of the 8th International Conference on Computer­Aided Architectural Design Research in Asia / CAADRIA (pp. 157‐164), Rangsit University, Thailand.

(36) Mitchell, W.J. (1984): “Computing the Forms of Things” in Arts + Architecture, Vol. 3 No.1.

(37) Mitchell, W.J. (1990): The Logic of Architecture. Design, Computation and Cognition, The MIT Press, Cambridge MA. (38) Mitchell, W.J. & McCullough, M. (1995): Digital Design Media, 2nd edition, Van Nostrand Reinhold, New York.

(39) Monedero, J. (1997): “Parametric Design. A Review and Some Experience”, in Proceedings of the 15th eCAADe Conference, Vienna University of Technology.

(40) Otto, Frei (2008): Frei Otto, Conversación con Juan María Songel, Ediorial Gustavo Gilli, Barcelona.

(41) Pottman, H.; Asperl, A.; Hofer, M. & Kilian, A. (2007): Architectural Geometry, Bentley Institute Press, Exton PA. (42) Ranky, P.G. (1986): Computer Integrated Manufacturing, Prentice‐ Hall, UK. (43) Rotheroe, K.C. (2000): The Computer­Aided Design and Manufacture Complexity­Shaped Metal Architectural Frame Structures, Doctor of Design Dissertation, Graduate School of Design, Harvard University.

(44) Ruhl, V.R. (1997): Computer­Aided Design and Manufacturing of Complex Shaped Concrete Formwork, Doctor of Design Dissertation, Graduate School of Design, Harvard University, Cambridge MA.

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(45) Sakamoto, T. & Ferré, A (Eds.) (2008): From Control to Design.

Parametric / Algorithmic Architecture, Verb Monograph, Actar, Barcelona.

(46) Schodek, D.; Bechthold, M.; Griggs, K.; Kao, K.M. & Steiinberg, M. (2005): Digital Design and Manufacturing. CAD/CAM Applications in Architecture and Design, John Wiley & Sons, Hoboken NJ. (47) Shea, K. (1997): Essays of Discrete Structures: Purposeful Design of Grammatical Structures by Directed Stochastic Search, PhD Dissertation in Mechanical Engineering, Carnegie Institute of Technology, Carnegie Mellon University.

(48) Shelden, D. (2002): Digital Surface Representation and the Constructability of Gehry’s Architecture, PhD Dissertation in Architecture, Design and Computation, Massachusetts Institute of Technology, Cambridge MA. (49) Teicholz, E. (Ed.) (1985): CAD/CAM Handbook, McGraw‐Hill, USA. (50) Terzidis, K. (2006): Algorithmic Architecture, 1st Ed., Architectural Press, Oxford.

(51) Thompson, D’Arcy (1961): On Growth and Form, Cambridge University Press, Cambridge.

(52) Thompson, R. (2007): Manufacturing Processes for Design Professionals, Thames & Hudson, New York.

(53) Wang, Y. & Duarte, J.P. (2002): “Automatic Generation and Fabrication of Designs”, Automation in Construction 11 (pp. 291‐ 302), Elsiever.

(54) Yun, Y.G. (2001): Structural Composite Members in Architecture, Doctor of Design Dissertation, Graduate School of Design, Harvard University, Cambridge MA. (55) Zeid, I. (1991): CAD/CAM Theory and Practice, McGraw‐Hill.

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Chapter 4

Cork and Architecture

4.1

INTRODUCTION

Encouraged by the verification that new digital design and manufacturing technologies have been opening innovative applications for old materials in architecture, this thesis proceeds by selecting a traditional material as a case‐ study to develop a more in‐depth theoretical and practical research.

Influenced by its ecological nature and its social and economic importance for Portugal, cork emerged early as a natural hypothesis to serve the purposes of this dissertation. With an industry mostly based on the production of cork‐stoppers, many derivate products from cork, like agglomerates, have been regularly used in building construction for more than one century. However, unlike other traditional materials, their apparent limited applications and the lack of research with digital technologies represented factors of uncertainty regarding the future of the material in building construction. Instead of being a problem, this was understood as an opportunity and an extra stimulus for accepting the risk of studying cork and its potential to match contemporary architectural interests.

In this context, the present chapter starts by providing a general background on cork. Reviewing state‐of‐the‐art literature, this overview summarizes the

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origins, properties, products, applications and the importance of cork at many levels nowadays.

Realizing the wide range of cork products available in the market, the decision of selecting a specific derivate to develop a more in‐depth analysis was a necessary step. The supporting reflections and arguments leading to focus the thesis attention on the pure cork agglomerate are then presented and discussed.

Research concerning its productive processes, properties, products and applications is developed with the intention of inquiring, among other things, into: 

the relevance of this material for the building construction industry in the present world;



the subjacent conditions that can drive to the emergence of innovative applications;

The chapter ends by envisioning the interest of using digital technologies to rethink its application in architecture.

4.2

REVIEWING CORK

4.2.1 The Origins

Cork is the material extracted from the cork oak which is botanically called as Quercus Suber1. The cork oak tree is also known as “Sobreiro” in Portuguese, “Alcornoque” in Spanish, as “Surer” in Catalan, “Chêne Liège” in French and “Quercia da Sughero” in Italian. Its material, cork, is also known as “Cortiça” in Portuguese, “Corcho” in Spanish, as “Suro” in Catalan, “Liège” in French ans “Sughero” in Italian. [Fig. 4.01] 1

Identifying Quercus Liber (Linnaeus) as the true name of the material derived from the Latim,

Gilbert E. Stecher, that Quercus Suber became the definite name of the tree to convey some particular meaning to the ancients (Stecher, 1914: 5).

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Figure 4.01

Cork and the cork oak. Men

stripping cork from the tree,

thickness of cork layer.

and a detail showing the

Cork and the Cork Oak tree

Suited to thrive in low‐fertile soils and adapted to hot and dry summers and warm winters, the cork tree finds its natural habitat in the Southwest European and Northwest African borders in the Mediterranean Sea [Fig. 4.01]. Covering almost all the Portuguese territory, where it is in the top of the most planted trees, the distribution of the cork oak tree extends towards Spain, especially to the interior south, Catalonia in the Northeast and Galicia in the northwest. As it can be seen from the following table [Fig. 4.02 and 4.03], these two countries have been clearly dominating the world of cork, with an advantage for the first one. Still influenced by the Mediterranean climate, France (Corsega and Provence), Italy (Tuscany, Sardinia and Sicilia), Alger, Morocco, and Tunisia rank next in importance .

Figure 4.02 Distribution of the cork oak forests in the Mediterranean Basin,.

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Distribution of Cork Tree

Figure 4.03

Cork Production

Table illustrating the distribution of the cork oak forest and the annual cork

Country

Area (ha)

%

Annual (ton)

%

Portugal

736,700

32,4

157,000

52,5

according to the Direcção

Spain

506,000

22,2

88,400

29,5

(DGRF) and APCOR, in 2006.

Algeria

414,000

18,2

15,000

5,2

Morocco

345,000

15,2

11,000

3,7

France

92,000

4

3,400

1,1

Tunisia

92,000

4

7,500

2,5

Italy

92,000

4

17,000

5,5

Total

2,277,700

100

299,300

100

production by country, Geral dos Recursos Florestais

Besides this geographic concentration in Western Mediterranean area, the recognition of the value of cork have stimulated other countries to develop efforts to artificially get the tree thriving in their land. One of the most persistent attempts happened in the United States by the hand of its third president Thomas Jefferson. Inspired by a visit to France in 1784 where he saw the cork tree, he initiated a serious of recommendations and plans to introduce and establish the cork tree in the country almost until his death in 1826. Without achieving the success, his vision continued to influence others to pursue his intents, leading to the planting of imported cork oak acorns in some regions like South Carolina and California in the second half of the 19th century, and to the massive planting plan around the country called the McManus Cork Project in the last century, between 1940 and 1949. Despite the persistence of the interest and efforts, it never led to productive results.

Santos (2002: 18) cites Joaquim Vieira Natividade (1899‐1968) summarizing, with some humor, that “the culture of the cork oak tree is a rich culture in our poor souls, and is a poor culture in the rich soils of the American country”2.

2

Joaquim Vieira Natividade was a Portuguese agronomist engineer and silvicultorist who

developed a recognized activity as a technician and a researcher. Throughout his career, he dedicated a special attention to cork and the cork forest, which is expressed in his seminal book called Subericultura (1950).

Geographically, the Iberic Peninsula clearly dominate in both cases, with Portugal being responsible of 1/3 of the planting area and more than a half of the cork production in the world.

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According to Gibson and Ashby (2001: 454), although thin layers of cork can be found in the bark of all trees, it is in the Quercus Suber that it forms a thick layer that can reach several centimeters around the trunk of the tree protecting it from heat, loss of moisture, animal damage, fire and other hostile outside conditions. Unlike other trees, once extracted, this protective layer reveals an unusual capacity for growth and regeneration, which opens “the possibility of using the cork oak tree as a sustainable producer of cork throughout its lifetime”, being “the basis for the use of cork as an industrial raw material” (Pereira, 2007: 7).

These singular features of the cork oak have been acknowledged since ancient times in many poetic, philosophical and scientific works3. One of its most detailed descriptions was expressed by the greek Theophratus (372‐ 287 B.C.). In his work on botany called Enquiry into Plants, he wrote that: “it is a tree with a distinct trunk and few branches, and is fairly tall and of vigorous growth. The wood is strong; the bark very thick and cracked (…) The leaf is like that of the manna­ash, thick and somewhat oblong. The tree is not evergreen but deciduous. It has always an acorn­like fruit like that of the aria (holm­oak). They strip off the bark, and they say that it should all be removed, otherwise the tree deteriorates.” (Cooke, 1961: 5).

In general, this is still a valid description of the cork tree today. In her book Cork Biology, Production and Uses, H. Pereira (2007: 106) adds that: “The cork oaks are low­spreading trees with a short stem and thick branches. The trees do not attain heights greater than 14­16m which can grow until 12­16m height, but open­grow trees may have very large crown dimensions, e.g. 500m2 of crown projection in some mature trees”.

Although man has used raw cork since the ancient times for simple purposes, the industrial exploration of the cork oak triggered a more profound knowledge about of its biology to assure its protection and maximize its

3

Almost all cork researchers converge in their references about ancient written works

featuring mentions about cork. In his book Cork and the Cork Tree (1961: 3‐7), Giles B. Cooke’s enumerates several of them providing some excerpts too.. Besides Theophratus, he points authors like Virgil (B.C. 70‐19), Horace (65‐8 B.C.), Columella (A.D. 20‐75), Pliny the Elder (A.D. 23‐79), Plutarch (A.D. 46‐120). The Spanish Cervantes (1547‐1616) is also noticed as mentioning by several times his native tree on his book “Dom Quixote”.

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productive potential. As a consequence, laws have been introduced to rule the exploration of cork oak nowadays, while more sophisticated applications for the material have been developed.

In this context, according to Portuguese laws, the exploration of the cork oak can only start after the tree has reached a perimeter of 0.7m measured 1.3m above the ground (i.e., chest level), which usually happens when it is around 20‐35 years old. Then, over an estimated 150‐200 years exploration lifetime, the cork oak is manually stripped every 9 or more years cycles, by skilled workers that use an ax to perform cutting and pulling operations.

Experienced as a cultural ritual, the extraction of cork planks usually takes place in the end of the spring and early summer, when the oaks’ regenerative process is active and the weather is more favorable for stripping.

Raw materials

Due to the tensions resulting from its radial growth, the tree initially produces a layer of cork that is hard and has a very irregular and cracked exterior surface (Fortes, Rosa & Pereira, 2004: 13; Oliveira & Oliveira, 2000: 123). It is known as virgin cork and this first stripping is called in Portuguese “desbóia”. All further strippings are known as reproduction, and they see the quality of cork improving overtime. Because the tree has not reached its adult stage yet, the first of these reproduction stripping still produces an irregular cork which is called secondary cork. After this period, the tree starts producing a more homogeneous cork, which is known as amadia cork4.

Finally, the pruning of the tree branches and leftovers from stripping gives also origin to a sub‐product called “falca”, which is a mix of virgin cork, inner bark and wood (APCOR, 2006: 98). While poorer raw materials like virgin cork, secondary cork and falca are grinded to produce agglomerates, the perfect quality of the amadia cork is used for the main industrial application – the production of the cork‐stoppers.

Apart from a technical knowledge interest, the understanding of these steps is important to realize the full value of the cork oak and the sustainability of its exploitation. On this respect, Gil (2005a: 136) highlights that “the 4

Both secondary cork and amadia cork are also known as reproduction cork.

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commercial exploitation of cork promotes its production by the tree, and this increment corresponds to a CO2 fixation equivalent to the pollution made by around 180 000 cars every year”, and that “each produced cork­stopper corresponds to the double of its mass in fixated CO2”5. Also, while no trees are cut‐down, all extracted raw cork materials tend to lead to different applications through many different industrial processes. The origins of the increasing diversity of cork products and applications available in the market are thus the result of a patient and harmonious relationship between man and the cork oak, which acquires a notable emotional level in its native regions.

4.2.2 Properties

Cork is a natural material that remarkably combines a wide range of physical and mechanical properties. This singularity is extended to a set of sensorial attributes that, distinguishing it from other materials, should not be ignored by any architect and designer interested in this material. As researchers have demonstrated, the secret for this notability lays in its internal structure and in its chemical composition6. Although some technological instruments were needed to scientifically uncover the microscopic reasons for cork’s singular properties, they have been empirically recognized since the ancient times by man in its popular applications.

The analysis of cork’s internal structure is directly connected to the microscopy history. It was one of the first elements observed by Robert Hooke (1635‐1703) who described his observations in his famous Micrographia book published in 1665. Hooke’s drawing showing cork’s 5

Personal translation from Portuguese to English.

6

In his book Cork: Its Origin and Industrial Uses from 1914, Gilbert E. Stecher provides some

information about the structure and chemical composition of cork. Acknowledging the singularity of cork properties, he refers a paper read at the Royal Institution of Great Britain in 1886 where Mr. William Anderson said that “an examination of its structure is easy and perfectly explains the cause of its peculiar and valuable properties” (1914: 25). More recently, Gibson and Ashy (1997), Gil (1998), Fortes, Rosa and Pereira (2004), and Pereira (2007) have provided detailed descriptions of studies about cork microscopic properties.

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internal structure similar to bees’ honeycombs is a classic of science, and that observation led him to coin the term “cell” [Figure 4.04]. Further studies conducted with advanced technologies throughout the XX century have confirmed many of Hooke’s early assumptions.

Figure 4.04 Drawing of cork cells observed in the microscope

by Robert Hooke, published in Micrographia (1665).

Thus, together with wood, sponge, bone or corals, cork belongs to the family of natural cellular materials. In parallel, man have been developing techniques to produce artificial cellular materials like polymeric, metal, ceramic or glass foams. In common, these materials are made of an “assembly of cells with solid edges or faces, packed together so that they fill space”

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159

(Gibson & Ashby, 2001: 1) and their relative density usually doesn’t exceed 0.30 (Fortes, Rosa & Pereira, 2004: 33).

In cork, these cells have an approximately elongated prismatic shape with an hexagonal section, configuring 14 sides in general. According to the following picture, their three‐dimensional stacking organization in space draws an anisotropic condition that varies according to radial, axial and tangential sections [Figure 4.05 and 4.06]. Made out of very thin walls with about 1150kg/m3 density, the cells are closed and filled by a gas that occupies about 90% of its volume. Considering an average volumic mass of 170 kg/m3 for cork, the relative density of this material is low, being around 0.15 (Gibson & Ashby, 2001: 456).

Figure 4.05 Diagram of cork tree (left).

Axis system and sections nomenclature (right).

Adding to its structure, the chemical composition of cork present some

Figure 4.06

decisive characteristics that influence its behavior. Its constitution is about

The three dimensional

45% suberin, 27% lignin, 12% cellulose and polysaccharides, 6% tannins,

left, an approximation of the

structure of the cork. On the

5% waxes and 5% ash and other compounds (Gil, 1998: 239). Among them,

cell’s shape and, on the right,

the suberin emerges as the main constituent of the cellular walls. Being

structure, revealing the

responsible for its imperviousness it is associated to lignin which as an aromatic character. Suberin’s decisive importance in defining cork properties is considered similar to that of cellulose in wood, where it is more than 50% of its constitution (Fortes, Rosa & Pereira 2004: 50).

the three‐dimensional cells’ anisotropic condition of the material.

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Both cellular structure, cell’s shape and chemical composition have a direct effect on cork’s many different properties7. For the purpose of the present dissertation the following ones are highlighted:



Lightness and Buoyancy With almost 90% of its volume constituted by imprisoned air on its cells, cork is one of the lightest solid materials. Its air‐filled cellular structure and impermeability draws its capacity to float in water, which is at the core of the first uses of cork acknowledged in human history. Cork’s buoyancy was explored as aids for swimming and as fishnets‐floats, while its lightness was appreciated for the production of shoes soles.



Compressibility Among the several mechanical properties of cork, compression is one of the most relevant ones. In this process, unlike other materials, “the material’s ability to undulate the cell walls allowing for a large deformation without lateral expansion” (Pereira, 2007: 212), which justifies it Poisson coefficient near 08. Considering its anisotropic quality, cork tends to go through three deformation phases under compression: cells’ elastic, buckling and collapsing behavior. While the first one admits shape recovery, the last one implies its irreversible densification.



Resilience The particular cellular structure of cork gives it a resilience behavior that “allows large deformations under compression without fracture, with substantial recovery when stress is relieved” (Pereira, 2007: 207)9. The undulating and viscoelasticity10 behavior of the cork cells enables its application as an outstanding sealing material. This

7

These observations are more clear and stable on amadia cork when this material becomes

more homogeneous.

8

Measuring the variation of dimensions of a material in directions perpendicular to the

compressive direction, the Poisson coefficient of cork is about 0.2. Negative values imply material contraction, while positive values imply material expansion.

Because cork’s dimensional recovery doesn’t occur instantaneously after the compressive

10

force disappears, its behavior is not purely elastic. The material’s property that describe a relaxation effect occurring in its own rhythm is called viscoleasticty (Fortes, Rosa & Pereira 2004: 163)

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potential can be easily observed in the cork stoppers’ ability to compress when entering in the bottle and to expand when leaving the bottle. For these reasons, and as most cellular materials, cork has thus a very good energy absorption rate that are very interesting for packaging, vibration absorption and other structural applications.



Imperviousness The presence of the suberine substance in the cell’s walls is considered by many authors as the responsible for cork’s almost imperviousness to gas, water and other liquids (Cooke, 1961: 22; Gil, 1998: 186). Its non‐capillarity makes it difficult the penetration of liquids through its cellular structure justifying its sealing behavior.

Facing humid conditions cork doesn’t have any tendency for rotting (Oliveira & Oliveira, 2000: 132). Nonetheless, when in persistent contact with water, it reveals a capacity to absorb a significant quantity of liquid, which alters some of its mechanical and dimensional properties (Fortes, Rosa & Pereira, 2004: 182). This fact is widely explored by the industry, for instance, in the dimensional stabilization of the stripped amadia cork before its transformation or in the production of the expanded cork agglomerate.



Friction Friction between two elements can be studied at the surface level – adhesion ‐ or considering the material’s thickness capability to absorb energy – anelastic loss (Gibson & Ashby, 2001: 465). Unlike absolute rigid or perfect elastic materials, cork’s viscoelasticity plays an important role as it tends to favor a high coefficient of friction, that is evident in contact with glass. Because this characteristic strongly depends on the anelastic loss processes that occur under the surface, it is not so relevant to alter cork’s surface adhesion with finishing treatment like polishing (Gibson & Ashbyn, 2001: 465)11.

Cork has thus interesting anti‐slipping characteristics.



Wear Many authors consider that there are very few detailed studies about cork’s resistance to wear. However, some laboratory

Cork‐stoppers usually receive a surface treatment with paraffin and silicone to reduce the

11

force needed to insert and remove it from glass bottles (Fortes, Rosa & Pereira 2004: 150).

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experiences have revealed a very low wear coefficient (Fortes, Rosa & Pereira 2004: 149, Pereira, 2007: 231). Withstanding against repeated rubbing, the use of cork in floors can be appropriate in scenarios with very intense use, as its resistance to thickness and mass loss is largely superior to Oakwood or Carrara marble (Pereira, 2007: 231). Cork is also claimed as a material that does not absorb dust, being favorable to sustain non‐allergic environments (Oliveira & Oliveira, 2000: 135).



Thermal All cellular materials have in general low conductivity of sound and heat. Cork’s low relative density, small sized cells and the imprisoned gas contribute to dissipates heat conduction, convection and radiation throughout its structure (Gibson & Ashby, 2001: 466).

For these reasons, although it has a higher density, cork’s low thermal conductivity is comparable to that of artificial foams, which positions it as a leading thermal insulation material. (Pereira, 2007: 232). When exposed to heat cork suffers some chemical and physical changes, which alter its mechanical properties. As a result, as mentioned before, the combination of heat and water treatments is widely explored by the industry. The stabilization of the amadia cork before its transformation or the production of the expanded cork agglomerate are two scenarios where cork’s chemical and physical changes can be positively explored. Also, in the presence of fire, cork demonstrate a good resistance, acting as a natural fire retardant (Oliveira & Oliveira, 2000: 135)



Acoustic All cellular materials have also low conductivity of sound. Although the cut‐cells of the exterior of cork contribute for sound absorption, researcher claims that there is not yet a comprehensive theory about the relation between the internal structure and the acoustic behavior of cork (Fortes, Rosa & Pereira, 2004: 170). Nonetheless, cork has demonstrated to be a very good acoustic insulation material, competing with open‐cells polymers and other fibrous materials in the market.

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

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Indentation The capacity to be indented and recover afterwards reveals another interesting quality of cork. Due to its viscolelastic cellular structure, the densification resulting from a sharp object indentation it highly localized. When the object is removed, the holes tend to close‐up (Gibson & Ashby, 2001: 467). This is what happens when using drawing pings in bulletin boards.



Sensorial and Psychological In pair with its more scientific qualities, there is a different range of properties that are also important in cork, especially for any architect or designer interested in exploring this material. Both microscopic and macroscopic properties described above sustain a set of sensorial and psychological properties that can have influence on the way man perceive and feel space and objects. Although this field can encompass some subjectivity, there are some aspects that cannot be ignored. Warmness, for instance, is a feeling that can be perceived at a distance by means of cork’s brown color and then confirmed by touching it, because of its warm surface temperature.

This aspect can be extended to an idea of comfort. Indeed, cork’s viscoleasticity sustain a soft tactile sensation when one touches or grabs cork objects. The particular cork’s smell or odor, is another feature of this natural material that should not be ignored. because it can aromatize a space. This list could be extended considering others emotional and cultural aspects, but then one would have to deal with progressively more subjective properties. What is important to retain is the richness of cork’s sensorial and psychological dimension waiting to be explored for conveying certain desired sensations.

4.2.3

Products and Applications

For more than four millenniums, cork has been a useful material for mankind. In a non‐industrialized world, cork was employed in its raw version as it came from the tree, and its applications were probably devised by the empirical recognition of its remarkable properties.

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Early products and applications

History record the oldest uses of cork in the production of fishing nets and accessories around 3000 B.C. in China, but also in the ancient Egypt, Babylon, Assyria, Phoenicia and Persia. Cork’s ability to float was also explored as an aid for swimming. In his work Parallel Lives, the Greek Plutarch (A.D. 46‐120) tells how the roman soldier Pontius Camillus carried pieces of cork under his clothes to help him swimming across the a river to accomplish a dangerous mission. The observation of cork’s imperviousness to liquids eventually drove its use for closing wine and olive oil vessels. The findings of some millenary amphorae with cork‐stoppers dating from the ancient Egyptian civilization seems to demonstrate the beginning of its use as a sealing material (Gil, 1998: 41).

Cork’s resistance and sense of comfort made it an interesting material for many other purposes. As mentioned in Cooke (1961), the Greek Pliny the Elder (A.D. 23‐79), adding to the previous applications, acknowledges in his Naturalis Historia work the use of cork in women’s winter shoes, while the famous Roman poet Virgil (70‐19 B.C.), in his masterpiece The Aeneid, describes the head of some soldiers covered by cork planks (Cooke, 1961: 4‐ 5). As these cases made evident, the realization of the material’s thermal insulating performance led to other applications like the production of bees‐ hives, as recommended by roman writer Columella (A.D. 20‐75). Acting as an excellent protection against extreme cold and hot temperatures, cork found a natural application in building construction, covering roofs in the ancient Greece (Oliveira & Oliveira, 2000: 22).

One of the most remarkable examples of cork’s great versatility that still can be observed today, is the Capuchos Convent in Portugal12. Built around 1560 it extensively employed cork in its construction benefiting from its qualities in many ways. Largely incrusted in a mountain, the building had to be protected against humidity and harsh temperatures. Raw cork planks were thus used to cover walls and roofs, but also to make interior furniture. Being left visible throughout the space, cork visual characteristics served as a decorative element that matched the humility and simplicity values of the religious Franciscans that inhabited the Convent. Its lightness also helped the The Capuchos Convent was originally named as Santa Cruz da Serra de Sintra Convent.

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transportation of this material to the construction site, from the distant extraction places. When visiting it today, it is possible to witness in this building the remarkable diversity of cork’s properties and their long‐time resistance and permanence over about 450 years. [Fig. 4.07]

Industrial Products and Applications

Overtime, the coupling of industrial developments with scientific research gave origin to a set of derivate products, which radically expanded the use of this natural material from basic applications to highly technological ones.

Figure 4.07 Fotos of the Capuchos Convent in Portugal, shoing the use of cork to cover walls, ceilings, doors and stairs.

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After many centuries of popular use, all researchers seem to agree that the origins of cork industry can be traced to the 17th century in France. At the Abbey of Hautvillers in France, the French benedictine Dom Pierre Pérignon (1639‐1715) realized that cork stoppers, unlike wooden ones, didn’t jump out the bottles containing sparkling wine. From then on, this natural sealing material became indispensable for wine bottling, and was adopted by important wine producers like Ruinart (1729) or Moet et Chandon (1743).

The increasing of its demand triggered the beginning of the cork‐stoppers’s induustry, first in the French localities of Landes, Var and eastern Pyrenees, then in Catalonia (1750) and finally in Portugal (1770)13 (Oliveira & Oliveira 2000: 33). In 1763, this activity was described by Dennis Diderot (1713‐ 1784), in his famous L’Encyclopédie, together with many other mechanical and craft arts. [Fig. 4.08]

Figure 4.08 Titled as “The Corkmaker”, the Plate 453 of Diderot’s L’Encyclopédie shows a corkmaker’s shop combining “petty manufacturing and merchandizing characteristic of 18th century commerce..

There, the owner and his apprentice cut cork stoppers, while his wife sort them and sells to the passing costumers, through the large

The growth of the cork stoppers production incited the adoption of more careful and rigorous exploration strategies. Grounded on exploring amadia cork, this industry generated a considerable amount of waste. On one hand, it discarded the use of inferior cork products, like virgin and secondary cork and falca, while, on the other hand, its productive processes created a lot of leftovers out of the amadia planks [Fig. 4.09]. Thus, finding a useful application for these products became an imperative concern.

Although it was known before in Portugal, “it was only around 1770, at the same time as the

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Port Wine trade began to flourish, that cork­stoppers became indispensable for preserving wine as well as allowing it to mature in glass bottles”

ahopfront opened to the street.

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Figure 4.09 Perforation of raw cork for making cork stoppers showing a large amount of wasted material.

By the end of the XIX century, the discovery of processes for agglomerating cork became a solution for the sustainable management problem and an opportunity for diversifying the range of cork products and applications.

Along with the existent industries of production, preparation, and transformation, the rise of the granulation and agglomeration industries contributed for a radical improvement shift14. While before only about 25% of the raw material knew a useful destination in the production of cork stoppers, now, the industries of cork can make use of the remaining 75%, to produce other valuable products (Oliveira & Oliveira, 2000: 145). The following diagram pictures the general production cycle of cork products, demonstrating the full utilization of raw and waste materials. [Figure 4.10]

The industry around cork can be divided in five major sectors: production, preparation,

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transformation, granulation and agglomeration. A clear review of these industries can be found in the book A Utiilização e a Valorização da Propriedade Industrial no Sector da Cortiça (Gonçalves, J., et al. 2005: 17‐22). Summarizing: the Production industry is concerned with the conservation of the cork oak forest and the stripping of its bark; the Preparation industry is oriented towards the cleaning and physical stabilization of cork planks for classification and selection; the Transformation industry is dedicated to perform manufacturing operations on the cork planks , like cutting, drilling or labeling, for the production and commercialization of stoppers and other products; the Granulation industry seeks to give full application for minor cork products or waste material resulting from the transformation industry, by means of triturating processes; the Agglomeration industry uses the granules to produce cork agglomerates by exploring several artificial and natural bonding strategies.

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Figure 4.10 Diagram of the cork applications resulting from the integral use of cork materials by the company AMORIM. “Refugo” is a term that designates the low quality cork that is not appropriate for the production of stoppers.

In resume, all cork products generated by the industry today can be classified as:



Raw Cork As explained before, one of the oldest and today’s main application of cork is in the production of natural cork stoppers with different sizes and qualities, directly from amadia cork planks. The fabrication of disks in raw cork is a growing activity, being used, for instance, in the production of technical or compound cork‐stoppers for champagne. In these products, this natural disks are used to end the tops of agglomerated cork‐stoppers. With a very small expression, raw cork is also used for the production of souvenirs and craft works. [Fig. 4.11]

Figure 4.11 Raw cork.

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Cork Granulates The triturating of inferior quality cork products and waste, gives origin to granulates. Current industrial processes allow for the production of granulates with different sizes, to suit the requirements for further material applications. The main application of cork granulates is in the production of different agglomerates and other composite materials. Nonetheless, they can also be used directly as an insulating material to fill empty spaces under floor pavements. Finally, the recycling of cork agglomerates can be made through granulation processes, giving origin to what is called as cork regranulate, that can be used for some of the purposes mentioned above. [Fig. 4.12]

Figure 4.12 Cork granules.



Pure Cork Agglomerate The pure cork agglomerate results from a thermal process that provoke the volume expansion and self‐agglomeration of the granules against the walls of an autoclave. Its origins can be traced back to 1892 in the United States, when John T. Smith accidentally discovered this singular physical and chemical behavior under heating conditions (Thomas, 1928: 29‐32; Faubel, 1941: 25). Also known as expanded or black agglomerate, pure agglomerate is made out of 100% cork and appear in the form of dark brown blocks and boards, exhibiting a texture with large granules. The main application of pure expanded cork agglomerates has been in the building construction industry, serving as a thermal and acoustic insulating material15. Traditionally, it is used hidden within walls, slabs and ceilings, or visible in interior conditions. Nonetheless, some architects and designers have recently pushed the application of pure cork agglomerate into other innovative situations. While Álvaro Siza initiated its use as an exterior cladding material in the Portuguese Pavilion at the 2000’s World Fair in Hannover, Jasper Morrison, the Bleach Design studio and AMORIM have conceived some outdoor furniture in pure agglomerate. [Fig. 4.13 and 4.14]

Denoting those functions, the international technical name for the pure cork agglomerate is:

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Insulating Cork Board (ICB).

Figure 4.13 Pure cork agglomerate.

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Figure 4.14 System of benches and stools designed by AMORIM.



Compound Cork Agglomerate Also known as white or simple agglomerate, compound cork agglomerate implies the use of adhesives to bond together the small triturated granules. The origin of this gluing strategy was not accidental but actually the result of several years of laboratory research. According to Faubel (1941: 70‐72), the beginning of the manufacturing of this artificial cork happened during the 1890’s in USA and Germany. As an interesting material for the cars industry that was going into mass production, for the crown makers and for shoes soils producers, the commercialization of compound cork was consolidated during the 1910s. Appearing today mainly in the form of blocks, boards, thin rolls or disks, this material exhibits a light brown color with an homogeneous grain texture, presenting also a very good flexibility. [Fig. 4.15]

The application of compound agglomerates are immense, and encompass the production of agglomerate cork‐stoppers, decorative panels, floor covering and wall paneling tiles, footwear, sports equipment, bulletin boards, domestic utensils, and even clothing and fashion accessories. Due to its visual and physical qualities, many designers like Daniel Michalik or Jasper Morrison have been attracted by this material to produce innovative furniture and product design works. [Figure 4.16]

Figure 4.15 Compound cork agglomerate.

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

Composites materials with cork Both the cork granulates and the previous agglomerates have been combined with other materials to create sophisticated and valuable

Figure 4.16 Chaies‐longue designed by Daniel Michalik (left) and vahir designed by Jaspers Morrison (right).

material composites. Discovered accidentally in 1863 in UK by Frederik Walton, the linoleum consisted in a ”mixture of oxidized linseed oil, finely granulated cork and gum pressed onto flax sheets” (Pereira, 2007: 247) and it has been used as a floor finishing material.

More recently, rubbercork or corkrubber was developed in the United States in the beginning of the 1960s, with the goal of combining the best features of cork with those of the synthetic rubber, compensating the weakest aspects of both materials.

Figure 4.17

Exhibiting interesting physical and visual qualities, it is used in

Rubbercork sheet.

“technological demanding applications such as gaskets and sealing systems in the automobile industry, vibration and acoustic insulation for industrial machinery, civil engineering and railways, gaskets for electrical transformers, heaters and gas meters or heavy­duty flooring and footwear” (Pereira, 2007: 296). [Fig. 4.17]

In building construction, it is possible to find other examples of composite applications like in the production of floating pavements by combining rigid wooden boards with compound cork agglomerate, or in the production of new insulating materials like Corkcoco, where pure agglomerate is associated with natural coconut fibers16. [Fig. 4.18] Corkcoco is a composite material of cork and coconut fibers developed and commercialized

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by AMORIM.

Figure 4.18 Corkcoco sandwicj products.

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Cork granulates and regranulates have also been used as an aggregate in the production of lightweight concrete elements. [Fig. 4.19]

Due to cork’s material properties and ecological value, the development of cork composites have become over the last decades a fertile ground for research17. On the one hand, many designers like

Figure 4.19

the Simple Forms, The Home Project or El Utlimo Grito studios, have

Lightweight concrete with

explored the combination of cork with other materials to produce

cork granules.

exceptional works that highlight the remarkable physical and sensorial qualities of cork. [Fig. 4.20]

On the other hand, cork has been explored in advanced industries,

Figure 4.20

like the automotive or the aerospace18, which refute the idea of cork

Simple Forms’s wash basin

as an old‐fashioned material, and places it on the edge of the highest

The Home Project’s design for

technological applications of nowadays. Da Veiga and Ferreira (2005: 64) envision future building materials in cork with even

design in rubbercork, (left). a set of drinking cups (middle)in compound cork and ceramics. El Ultimo

augmented capabilities, claiming that: “composite materials made

Grito’s chair “Miss Ramirez”

from cork dust reinforced with carbon nanotubes could be capable of

in compound cork with

achieving high tensile strengths and significant ductibility, while acting as acoustic and thermal insulators”.

In a visit to the Portuguese Cork’s Technology Unit (UTC) at the INETI (National Institute of

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Engineering and Industrial Technology), it was possible to consult an extensive database of patents registered involving the use of this material and verify the incredible wide range of its applications. The Unit’s director, Luis Gil, has been interested in generating new cork products, with potential interest for architecture. Having some patents, the densification of the expanded cork agglomerate through pressure processes and the design of new composites by mixing cork with recycled cardboard and tetra pack are some interesting examples of his fascinating work.

The AMORIM Industrial Solutions produces a cork granulate called Cork Composition, which

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is especially produced for NASA rockets. According to the producers, “This material is used for lining the engines and acts as an insulating agent against the high temperatures that occur in this area. This is only possible thanks to the unique characteristics of cork.” (http://www.realcork.org/artigo.php?art=414, visited on June 2009).

rubber coating (right).

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Cork Powder and other sub­products The cork powder is generated in large quantity by the transformation and granulation industries19. Because both the inherent processes and the types of cork involved are diverse, different cork powders are generated. To a large extent, this sub‐ product has been used as a combustion fuel for the factory boilers of the cork and ceramic industries. To a small extent, some thicker powder also has been used as a filling material in the production of some agglomerates, and as a cleaning material of objects exposed to environmental pollution. The extraction of some valuable chemical components from cork or the re‐use of other residues, like condensates obtained from the boiling steam during the production of pure agglomerate, can also find applications in other areas, like in the pharmacy and chemical industries (Gonçalves, J., et al. 2005: 27).

Given the diversity of cork products enumerated above, it is important to understand their relative importance from a commercial perspective. The following graphic from the Portuguese Cork Association (APCOR), illustrates the organization of the business structure in Portugal [4.17]. Given the leading role of this country in the world scene, this information can be considered as valid at the international scale.

Figure 4.21 Structure of cork sales per product year in 2007, according to APCOR.

The most important observation consists in verifying that cork’s commercial structure has been characterized by the primacy of the cork‐stoppers. As it was described before, cork‐stoppers are not only at the origins of the cork’s

Gil (2005: 95) estimates that in Portugal, the production of cork powder is around 40.000

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tons every year.

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industry but represent today about 70% of the whole business, which is clearly focused on the winery industry. The commercialization of cork agglomerates, mainly oriented towards the building construction industry, ranks next in importance but at a considerable distance. Separately, all other cork products do not represent more than very small niches within the overall structure.

4.2.4 Significance

The selection of cork as the case‐study material for the disciplinary and technological purposes of this dissertation, assumes a double significance. By doing that in Portugal, where cork has a crucial economic importance, and in the present moment of our history, when ecology and sustainability are major politic and social concerns worldwide, the scope of this research spans both local and global scales.

Local Significance

With the concentration of the cork industry in the Iberian Peninsula that occurred between 1920 and 1970, Portugal started to take on the world leading role that Spain had played since the 18th century (Cooke, 1961: 62‐ 64; Zapata, et al. 2009: 189). As shown before, Portugal clearly dominates today the world’s production of cork. According to the United Nations Statistics in 2005, it is possible to see that its dominance also extends to the transformation and commerce business, being responsible for 60% of the whole trade. [Fig. 4.22]

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Along with this external prevalence, the industry of cork is internally one of

Figure 4.22

the most important economic sources. According to the Portuguese National

Main cork exporters

Institute of Statistics (INE), the economic revenue of cork exportations represents about 0,7% of the country’s Gross Domestic Product (GDP), 2,3 % of the value of the whole Portuguese exports, and 30% of the total of forest products exports (APCOR 2009: 25).

In this context, the decision of selecting cork as a case‐study material for this research has a special meaning when it is done in Portugal, due its economic significance and impact expectations. Despite the traditional preference for cork as the best sealing material for the winery industry, the last decades the emergence of synthetic materials substitutes started to be a serious threat the sector20. While the industry struggles to keep its competitive advantage in this sector, today, is more important than ever to reinforce the competitiveness of other cork products by means of research and innovation According to Zapata (et al. 2009: 190), the appearance of the synthetic materials in the mid‐

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twentieth century have made most developed countries lost their interest in the cork’s industry, which was a major contribution for its concentration in the Iberian Peninsula. The United States played before a leading role in the industry, being responsible for many innovations,

worldwide in 2004 and 2005.

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practices. In this scenario, the present dissertation is thus inscribed in the contributions to rethink the use of cork in building construction, which, as showed before, represents the second most importance commercial business.

At the same time, given that most important companies in the world are located in this country, such a research could not be dissociated from the developments taking place in this country. As one of the goals of this dissertation is to go beyond the university boundaries to establish a direct connection with the industrial reality, a collaborative relationship with a company of the sector was aimed from the beginning. Being in Portugal, the possibility to establish a link with the company AMORIM21 through its branch AMORIM Isolamentos, became an opportunity and a privilege. With activity in 103 countries, AMORIM is the largest cork company in the world producing and trading about 30% of the world’s cork production.

Global Significance

Recently, the world has finally become aware about the continuous erroneous policies followed by man during the last century, at many levels like urbanization, energy, economy, manufacturing or mobility strategies. As a result, the future of the planet currently faces unprecedented environmental threats that appeals for a higher collective and individual awareness about the sustainability of humans’ presence and action on this world.

Partially responsible for the actual situation, the building construction industry cannot remain indifferent to the situation. As well as politicians, manufacturers and other leading agents, designers and architects have an important word on this subject, as they choose the materials with which, products and buildings that shape our world are made. In pursuing more sustainable oriented decisions, while advancements in technology can suggest the use of new materials, to rethink traditional ones and their life cycle is an essential research agenda towards a more eco‐efficient design responsibility.

To understand the dimension and organization of AMORIM company, a visit to its website is

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recommended. On June 2009 it could be accessed at: www.AMORIM.pt

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In this context, cork emerges as an old material with great potential to play an invaluable role, due to its great ecological value. As explained before, it is a natural, renewable and biodegradable material that is inscribed in a highly sustainable life cycle of production, transformation, application and recycling. Unlike other wooden materials, cork exploitation implies the maintenance of the cork oak, which is the fundamental pillar of a precious natural ecosystem. Contributing for the hydrologic regulation of poor soils and playing a resistance function against fire, the cork oak forest helps sustaining a rich biodiversity while its exploration helps fixing population thereby avoiding the human desertification of, otherwise, inhospitable areas.

(Oliveira & Oliveira 2000: 75‐88).

The exploitation of cork in the scope of this research has thus a global significance that transcends the boundaries of a country to be aligned with an important concern that worries the world nowadays. The economic reasons that in the past prevented some countries from playing an active role in its industry, the competitiveness of other cheaper and artificial materials, and the technical ignorance about its interesting features, seemed to have constrained the real potential for the application of cork in building construction. The present time seems thus to be a privileged moment to rethink the use of cork, as well as other natural materials, in architecture and building construction.

4.3

THE PURE CORK AGGLOMERATE

4.3.1 Research interests

After the general overview of cork as a natural and industrial material, it was necessary to make a decision about the cork material to be used as a case‐ study in the development of the practical research parts of this thesis.

Following the premise of rethinking an existent material through the use of

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CAD/CAM technologies, this selection process started by looking into the diversity of cork products that could be somehow related with building construction. Among them, cork agglomerates (compound and pure) and composites (rubercork) immediately emerged as possible options. However, with the nature of the technological experiments in mind, an initial comparative reflection led to the selection of the pure cork agglomerate as the material that could be worth for further investigation. The thoughts supporting this decision took into consideration some personal intuitions, as well as a set of more objective arguments based on the following reasons, that will be explained next: 

Architectural



Ecological



Research

Before commenting on them, it should be clarified that it was decided to follow the term pure cork agglomerated instead of its other existing designations, for two reasons22: 

to keep open other uses than just the insulation goal;



to emphasize its 100% natural condition.

Architectural reasons

As discussed before, architects in the Information Age have revealed a strong fascination with the form and surface qualities of buildings23, supported by the exploration of advanced digital design and manufacturing technologies.

Consequently, building facades have are the territory by excellence where the majority of the architectural, political, economical, and social forces’ attention are nowadays concentrated. In this context, it seems strategically In this reflection, the international term “Insulation Cork Board” seemed semantically

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restrictive in the scope of this dissertation, because it induces a specific application. In a similar way, “expanded agglomerated cork” could be limited facing older non‐expanded products of pure agglomerates or newer products like the compressed agglomerates. Finally, black agglomerated cork was depicted because it is considered to be a more popular term originated by its color.

See on chapter 4 the emergent architectural interests, in large part motivated by the use of

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new technologies in practice.

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pertinent for the cork industry to consider the application of its products in outdoor facade solutions. Continuing insisting only on cork products simply as insulating or interior finishing materials, would automatically keep this material tied to secondary applications and far from engaging in current dominant architectural interests. For these reasons, this part of the research focus its attention on the material’s capacity to define the buildings’ exterior appearance, becoming an attractive material for architects today for aesthetic and performative exploration by means of digital technologies.

Encouraged by some interesting examples of product design works, compound cork and rubbercork materials present a set of visual and mechanical qualities that make them, on a first glance, more appealing than pure cork agglomerates. However, because the nature of architectural products is radically different than that of product design works, material selection processes within each discipline are guided by different goals and constrains that can lead to different evaluations.

For instance, when considering the scale of architecture, the approach to material cost is different than in product design. While a designer can conceive a small piece in rubbercork material by arguing about its uniqueness and added value, it is almost impossible for an architect to imagine and economically sustain a building facade with this highly expensive material, when cents of large and thick components would be needed. Targeting this kind of architectural application also discourage the use of compound cork agglomerate. Based on a tradition of indoor use, this adhesive‐based material does not resist well to weather conditions. To overcome this problem would imply focuses research attention on resins and protective coatings issues, which is not the real goal of this work. In such situations, the efficiency of such products would be thus sustained by non‐ cork materials, which does not seem very interesting in the scope of this research.

Without involving adhesives, pure cork agglomerates are less expensive materials24 that can resist well to weather conditions. Moreover, current

Fortes et al. (2004: 239) explains that because adhesives are more expensive than cork, the

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size of the granules used for the production of compound cork agglomerate have a direct influence on the final cost of the product. If larger granules are used, less adhesive is needed and less expensive becomes the final product.

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industrial production systems fabricate blocks and boards with large formats and thicknesses that are suitable to tackle the scale of architectural buildings.

Realizing these factors, Álvaro Siza decided to challenge the traditional understating of pure cork agglomerate as insulating and hidden material. In his Portuguese Pavilion for the 2000 Expo in Hannover, he employed pure cork agglomerate blocks as an exterior material covering the building facade.

By exploring simultaneously the aesthetical and insulating potential of cork agglomerate, Álvaro Siza opened a new avenue for cork applications in architecture, which strongly influenced further thinking and research on the use of pure cork agglomerates in building construction.

Ecological reasons

Unlike compound cork and rubber cork products, pure cork agglomerates result from a self‐agglomeration process that does not involve any additional adhesives. For this reason, they are 100% natural materials that can be fully recycled into other products.

Furthermore, there are some references that demonstrate the exceptional durability of pure cork agglomerates, which are capable of resisting in perfect conditions overtime. In a study mentioned by Gil (2005b: 110‐111), the analysis of the thermal conductivity of pure cork agglomerates obtained from a 50 years old freezing tank, and from a 30 years old building that was demolished, revealed that the insulating performance of those rescued old materials were identical to that of new agglomerates. These observations are extremely relevant because they open the door to the reuse of this material in architecture25.

Another interesting aspect of pure cork agglomerates lays in the fact that its production process is less demanding concerning the quality of the raw material used. According to Gil (2005a: 90), it can employ the low quality cork materials that cannot be supported by the compound cork agglomerate and rubber cork’s production processes.

The worlds’ leading cork company AMORIM as a curious plea. Every time a building where

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pure cork agglomerate was employed in its construction is going to be demolished, AMORIM wants to be called to go there and pick up the material for reuse.

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With the current world concerns with sustainability in mind, the unique ecological value of pure cork agglomerates became thus a strong motif for exploring this material instead of other ones.

Research reasons

By the end of the 19th century, many innovations in the cork industry were introduced by countries that were not cork producers, like the United States of America, United Kingdom or Germany. According to Zapata et.al. (2009: 190), by the mid of the 20th century, the rise of synthetic materials as substitutes for many cork products started to move this countries away from the cork business26. Progressively, the industry became concentrated in the Iberian Peninsula and primarily focused on the cork‐stoppers production.

The main consequence of this tendency was the stagnation of innovation dynamics in the sector. Only a few companies, universities and research centers from the cork producing countries, mainly Portugal and Spain, have continued that role27.

Due to its economic importance, the majority of the research initiates taken in the last decades have focused on the cork‐stoppers industry. Other efforts have been developed, for instance, towards the diversification of the compound agglomerate products and the generation of new composite materials. Industrial production in these sectors have thus benefited from the

The American company Armstrong Cork started in 1860 as a cork‐cutting shop to become, by

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the end of the 19th century and the beginning of the 20th century, one of the largest cork companies in the world, and a major responsible for the introduction in the market of new cork products like the pure cork agglomerate and the linoleum. Depending on other countries to get access to the raw material, this company started to become progressively more interested in other products like fiberboards or vinyl floors. Reflecting this tendency, the company abandoned “cork” in its name, and it is today known as Armstrong World Industries. A brief history of the company and its pioneer role in the cork industry gave origin to a book written

by Prentis Jr. (1950).

In this respect, Gil (1998: 130) mentions the study “State of the Art of the European Research

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about the Cork Oack and Cork” (personal translation from Portuguese). Elaborated in 1995, in the scope of a European Community support, this document acknowledges that great part of the research has occurred in universities and research centers and less within the production companies. Gil (1998: 296‐297; 2005: 130‐131) also provides an extensive list of the scientific and technological centers associated to the cork industry. In his research it is possible to verify the actual dominance of Portuguese and Spanish institutions.

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progressive incorporation of advanced scientific research and new production technologies to innovate at both machinery and product levels.

In contrast, the industry of the pure cork agglomerate has subsisted overtime without significant modernization. Its current production systems are still based on rude mechanical equipments that sustain rigid modes of production based on standardization principles. At the same time, the final products in pure cork agglomerate available in the market have not suffered relevant changes overtime. Luis Gil’s work on developing densification processes to manufacture high‐density pure cork agglomerate28 is one example of the few initiatives with that goal.

In addition, this research did not find any particular study about the use of CAD/CAM technologies with pure cork agglomerate. On the contrary, there are plenty of digital research and applications in architecture involving the study of other traditional materials and, in the world of arts and industrial design, there are some works and products with compound cork and rubber cork produced with the help of digital manufacturing processes29. Instead of being perceived as a negative condition, the lack of digital research on this material is a risk, indeed, but constitutes a real opportunity for innovative investigation. Furthermore, and following the methodological premises of this research, the regular practical experience with digital manufacturing processes with other materials fed my intuition with the potential interest of investigating the use of CAD/CAM processes with blocks and boards of pure cork agglomerates for architectural applications.

4.3.2 Production Process

Current manufacturing processes for the production of cork agglomerate are the industrial application of the accidental discovery in the end of the 19th century, of the cork’s unique ability of self‐agglomeration under heating These processes have been already developed and registered in the Portuguese Patent N.

28

100647.

See 2.4 of this research, about the digital impact on materiality.

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conditions. Thomas (1928: 29, 30) relates that, by then, in John T. Smith’s boat building shop in New York, one of the many cylinders filled with granulated cork used for boat fenders, life preservers and ring buoys, inadvertently rolled next to the firebox in the end of a working day. In the next morning, when he was cleaning the firebox, Smith found the misplaced cylinder and observed, surprised, that the hot ashes did not consumed the cork particles, but bind them into a unique cylindrical brown mass. By testing that procedure several times, he concluded about cork’s self‐agglomeration effect under certain heating conditions. Denominating his discovery as “Smith Consolidated Cork”, he patented its manufacturing process in October 1892 (Faubel, 1941: 25).

Since then, the industrial production of pure cork agglomerates have followed a few different strategies, which are classified by Gil (1999: 169) as dry and humid processes. While in the first one, cork granulates suffer a thermal treatment in ovens, in the second ones, they suffer a thermo‐ chemical treatment in autoclaves. This last process is the one used in the industry today, and is also known as “steam backed”.

A precise understanding about the current production of the pure cork agglomerates came from a visit to the AMORIM factory in Vendas Novas, in Portugal30. Before getting in touch with the industrial processes, the first impression of this visiting was the observation of the perfect integration of the industrial facilities in the natural environment. Although smoke could be seen leaving the chimneys, many birds were flying in the sky like a demonstration of their non‐toxic characteristics31 [Fig. 2.23].

This visit was arranged by Mr. Carlos Manuel, the General Manager of the AMORIM

30

Isolamentos, a sub‐company of AMORIM responsible for the production and commercialization of pure cork agglomerate. The first visit occurred in April 2004, and was guided by Mr. Lopes Infante, the engineer that leads the factory.

This consideration is explained by Gil (2005: 107).

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The manufacturing of the pure cork agglomerates follows a sequence of steps

Figure 4.23

that start from the collection of cork raw materials that are not used in the

AMORIM factory in Vendas

production of other cork derivate products. Constituted by falca, poor virgin

Novas, Portugal.

and secondary cork, refugo, etc., these elements are stored in huge piles outdoors in the factory, being thus prepared for further processing. [Fig. 4.24]

The next step consists in the granulation of the mixed cork pieces. Using a

Figure 4.24

sequence of grinders, they are triturated and reduced to granulates with an

Poor raw cork materials

average size ranging from 4 to 21 mm. Although this process can be considered similar to those used in the production of other agglomerates, the size of the granulates is considerable bigger and have a wider variation tolerance32. The further cleaning of the granulates produces a material loss of about 30‐35% of the initial mass. The eliminated impurities are mainly cork powder and other denser elements, like remaining wooden pieces.

The production of compound cork agglomerates uses granulates from 2 to 6 mm. This size

32

can be even smaller in the production of ruber cork (Gil, 2005a: 85).

stored in piles outdoors.

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Then, cleaned cork granulates are ensiled and suffer a drying process in

Figure 4.25

order to reach the desired moisture percentage for the following steam

The granulation process of

backing treatment. The temperature reached in the silos cannot be too high, otherwise, the cork granulates would initiate their chemical transformation.

The next phase is the agglomeration process in autoclaves through a boiling process. Dried cork granulates are deposited inside the rectangular autoclave box, which act as a mold throughout the agglomeration process. Once it is packed, the top of the autoclave closes down and there is an initial compression to help compacting the granulates as a whole. The strength of this pre‐compression, together with the amount of granulates that were introduced, are the two factors that determine the final density of the blocks.

While regular blocks are produced with 120kg/m3, this process can be optimized to achieve a maximum around 320 kg/m3. Then, the boiling treatment is initiated. During approximately 20 minutes, superheated water vapor, at a temperature of about 300‐350 ºC, is injected in the autoclave through its bottom and lateral entrances. When the steam crosses the granulate mass until leaving out through exit tubes, it produces important chemical and physical alterations in the cork33. According to Pereira (2007: 298), during this process, some extractives and structural components are decomposed and get volatilized, making cork lose about 25‐30% of its original mass. However, by straightening its walls, the cells’ volume increases about 100%, which explains why this pure cork agglomerates are also known as expanded agglomerates. Closed in the autoclave, the pressure of cork granulates against each other together with the action of some chemical A concise description about the chemical and physical transformations produced in cork by

33

heating treatments can be read in Fortes et al. (2004: 200‐209) and in Pereira (2007: 233‐235).

A detailed description about the steaming process and its effects on the cork granulates during the steam backing process is provided by Gil (1998: 170‐172), Fortes et al. (2004: 242‐246) and Pereira (2007: 296‐302).

cork.

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compounds of cork produces their self‐agglomeration, which forms a whole pure and compacted block, with a dark brown color. [Fig. 4.26]

Figure 4.26

The steam boiling process

that produces the self‐ agglomeration of cork inside autoclaves.

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After the boiling process, the bottom part of the autoclave lifts the agglomerated block, which is then moved into the cooling area. At this moment, the blocks have a very high temperature, especially in their interior core, and present some small pieces in combustion. To face this, they are injected with a set of showers with recycled water at about 100ºC. Because of the material’s heating energy, they should be under control for some time to prevent auto‐combustion34. [Fig. 4.27]

Finally, when their temperature gets to normal, the blocks of pure cork

Figure 4.27

agglomerate become physically stabilized and follow for cutting and finishing

Pure cork agglomerate blocks

operations. Initially, a thin layer of their surfaces are cut to achieve the

the autoclave.

cooling down, after leaving

standard dimensions of 1500x500x300mm and provide a better finishing.

Then, a series of pre‐adjusted band saws and disk saws, cut the blocks in 1500x500mm boards with normalized thicknesses [Fig. 4.28 and 4.29]. A mechanical polishing rectifies and smoothes the surface of the agglomerates, preparing them for packaging [Fig. 4.30]. In the end, pure cork agglomerate packs are stored, for further transportation and commercialization.

Figure 4.28 Serial cutting of the blocks in standard thicken boards.

According to Gil (1998: 172), the high thermal energy of the pure cork agglomerate makes

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possible that auto‐combustion can occur until 10 hours after the backing process.

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Figure 4.29 Cutting thicken boards in two.

Figure 4.30 Polishing the pure cork agglomerate surfaces.

The close observation of the pure cork agglomerate’s industrial manufacturing process raises some important comments on its sustainability and flexibility.

On the one hand, from the ecological and environmental point of view, it was interesting to notice that during the process: 

everything occurs with no additives, like adhesives or finishing products for decoration or protection;



despite its depreciated dimension, the cork powder released throughout the process is combusted to serve as a natural fuel for the steam production;



the waste material obtained from cutting and finishing operations is collected and triturated to manufacture another product ‐ the re‐ granulated cork;



the vapors are usually released directly to the atmosphere without any treatment, due to their non‐toxic properties.

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Figure 4.31 Powder and granules released during the production process are collected and used as combustion material.

On the other hand, current production processes are ruled by mass production principles based on standardization. The granulometry’s selection mechanisms, the autoclave’s size and shape, and the saw’s serial positioning, gives few margin for size variation within the production set‐up.

Relying more on composition aspects rather than in formal ones, current opportunities for variation in the production processes can be found in: 

granulometry



density



thickness cutting

However, once the process is running, it is hard to change these parameters, which have to be manually and mechanically pre‐set in the different machinery. Such specifications thus rule a system the mass production.

Without any flexible digital control, this production process builds its efficiency on the paradigm of repetitive fabrication. After the production of standard pure cork agglomerate products, other initiatives can then occur to customize them, like, for instance, by doing new cutting operations.

4.3.3 Properties

Being a 100% cork product, pure cork agglomerate preserves some characteristics of the original raw material, while others suffer alterations due to the effects of the heating treatment.

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Although its history as an insulating material is older than most of its competitive products, pure cork agglomerates are narrowly documented in international literature about building construction. Hegger et al. (2006, 2007), Hughes et al. (2007) and Pfundstein et al. (2008) were some of the consulted publications where cork was briefly described.

The reasons behind this lack of divulging in the architecture field today, cannot be detached from the concentration of the cork industry in the Iberian peninsula, and the emergence of other competitive insulating materials.

However, testifying the importance that this material had in developed countries in the past, many early literature tackling the properties of pure cork agglomerates were produced in the Unites States of America, like the works by Quigley (1928) or Faubel (1941). The first, and oldest, of these books is an impressive publication given its heavy‐thick 500‐pages dedicated to the properties and uses of cork as an insulating material35. Nowadays, actual and concise information about pure cork agglomerates may be found in works mostly written by material scientists and engineers, like Gibson & Ashby (2001), Gil (1998, 2005b), Fortes et al. (2004) or Pereira (2007), and also in technical documents published by the cork manufacturers, like AMORIM.

Based on the reference works consulted, and considering the particular interests of the building construction industry, the following properties of pure cork agglomerates should be highlighted:



Isotropic Unlike raw cork, this material can be considered generically isotropic because, as Gil (1998: 217) states, “the distribution and orientation of the individual anisotropic cork granules happens randomly”36. However, the presence of impurities in its composition,

Consulted in the University of Pennsylvania, this book (Thomas, 1928) is a notable work with

35

plenty of graphic and analytical information about the use and performance of cork insulating boards. The field of application is in the construction of freezing chambers and architectural buildings, and contains many technical drawings about several design solutions as well as comparative analysis with other concurrent materials.

This feature was also acknowledged in a conversation with the material scientist Maria

36

Emilia Rosa, professor at IST and a researcher on cork. My goal in knowing about the isotropic condition of pure cork agglomerates was related with my interest in envisioning the possibility of using CAE software, like ANSYS, to determine its thermal or structural performance.

Isotropic materials are much more easier to program engineering simulations with the

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like burned wooden pieces, can introduce punctual changes its behavior. This fact can be minimized by the careful selection of the raw material.



Density Current used industrial production processes allow for the production of agglomerates with densities ranging from 80 to 320 Kg/m3. In the market, the average commercialized density is about 120 Kg/m3. Thus, pure agglomerates are heavier than other insulating materials, but lighter than other structural or finishing materials like wood. Therefore, they are considered as lightweight materials with buoyant capacities. The density of the pure cork agglomerate is determinant for many of its performative attributes.

It should be also included here a reference to a patented process about the application of pressure on the boiled blocks leading to its densification and the resulting production of boards with about 750Kg/m3 37.



Compressibility Due to its granulate composition, the compressibility of pure cork agglomerate is isotropic. Under increasing compressive forces, it presents a non‐linear deformation similar to the raw cork behavior and other cellular materials (Fortes et al., 2004: 245). Its viscolastic properties still allow for some deformation with further recovery, justifying it as a high resilient material. With a Poisson coefficient near 0 (Gil, 1998: 218), pure cork agglomerates do not suffer significant lateral expansion during compression. For these reasons, this material can be interesting for exploring masonry‐type structures in architecture.



Tensioning and Bending The presence of non‐cork particles in the material impedes the natural strong adhesion between cork granulates. The resulting porosity contributes for the material’s disaggregation or fracture under tension or bending forces, or even human action by hand. The

computer. However, the heterogeneity of the agglomerates, caused by the random impurities that it contains, should be considered when doing and interpreting such simulations.

Portuguese patent N. 100647 registered by Luis Gil / INETI.

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increase of the fabricated density and a more careful elimination of impurities in the raw material can improve the overall resistance to these kind of forces. Meanwhile, the exposure of pure cork agglomerates to these situations can be problematic in building construction due to the disaggregation possibilities.



Insulating The agglomerate morphology of the blocks and the cellular structure of the cork granules draw the very good insulating properties that characterize this material. Depending on the fabricated density and granulometry, pure cork agglomerates can be optimized for thermal, acoustic or anti‐vibration purposes [Fig. 4.32]. The materials’ density, granulometry, thickness and the amount of impurities presented in its composition are additional factors that interfere in the final insulating performance of pure cork agglomerates.

Figure 4.32

Pure Cork Agglomerates - Types

Granulometry and densities of manufactured Pure Cork

Type

Granulometry (mm)

Density (Kg/m3)

Acoustic

5-10

80-100

Thermal

5-32

100-150

Vibration

5-32

175-320



Water/Moisture absorption The granules’ internal cellular structure and their strong agglomeration38 creates a barrier for the penetration of water. At the same time, some chemical constituents are reported to be hydrophobic which difficult the absorption of moisture and the diffusion of water vapour (Silva et al. 2005: 359). However, the interfering presence of the non‐cork particles introduces some porosity and consequent hygroscopicity, which tends to stop after an initial penetration depth. Besides these features, pure cork agglomerates have a very good resistance to water.

Pereira (2007: 299) describes that “in well­bonded granules it is not possible to distinguish

38

which cells belong to each granule.

Agglomerate.

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Fire resistance Pure cork agglomerates have demonstrated a good resistance to fire tests. With slow burning behavior, it creates a superficial carbonized layer that is almost incombustible, making it a fire retardant material. Unlike other synthetic insulating materials, pure agglomerates do not easily fuse. They keep for a considerable longer time its formal resistance, while releasing fumes that are considered non‐toxic (Gil, 1998: 219). These features are of extreme importance in emergency situations in building construction.



Ecology As said before, pure cork agglomerates are 100% natural cork materials, that are inscribed in a sustainable and renewable life and energy production cycle (Pfundstein et al., 2008: 96). Without employing any kind of adhesive, they can be reused or fully recycled into new products, demonstrating an outstanding ecological value, especially when comparing with other insulating competitive materials.



Durability Resisting to a broad range of temperatures (i.e., ‐20ºC to 90ºC) that cover the building construction exposing conditions, there are several cases where pure cork granulates were analyzed after dozens of years of usage, and demonstrated to keep intact their qualities39. Without aging and rotting over time, pure cork agglomerates does not react to chemical and biological agents.

Furthermore, they do not provide nutrients for rodents and insects, and it is said that it does not promote the accumulation of dust. For these reasons, cork is acknowledge as a durable material hat does not carry any health risks.



Sensorial and Psychological Pure cork agglomerates have a dark brown color which conveys a warmth visual feeling and touching sensation. When exposed to the sunlight, this color tend to become lighter overtime, which is not necessarily a negative aspect. As it happens with other materials,

Gil (1998: 220) identifies several studies that were conducted over pure cork granulates used

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as thermal insulators in buildings and cold storage rooms, and as anti‐vibration materials for industrial machines.

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like cooper, this feature can be creatively explored to make the building appearance change over time. Regarding its surface qualities, some mixed impressions can be felt when touching this material. On the one hand, the surface is, to a certain extent, rough, but because it is also elastic and warm, it provokes an immediate sensation of softness. Another curious feature is the presence of a persistent and harmless odor that is released by this material, which is an important factor to consider in interior applications in building construction. Therefore, pure cork agglomerates are natural and, in a certain way, living materials.

After this overview of several properties of pure cork agglomerates, it is important to complement it with some more scientific information. Focusing on its most common density range, the general technical information that characterize pure cork agglomerates are summarized in the following table.

[Fig. 4.33]

Figure 4.33

Mean Characteristics of Pure Cork Agglomerate

Mean characteristics of pure cork agglomerate cork

Density

100-140 Kg/m

3

according to Gil (APCOR, 2006).

Thermal Conductivity Coefficient Θm = 23ºC Specific heat (to 20ºC) Thermal expansion Maximum pressure in elastic conditions Modulus of Elasticity (compression) Thermal Diffusion Poisson Coefficient Water Vapor Permeability

0,039-0,045 W/m. ºC 1,7-1,8 kJ/kg. ºC 25-50 x 10

-6

50 kPa 19-28 daN/cm2 2

0,18-0,20 x 10-6 m /s 0-0,02 0,002-0,006 g/m.h.mmHg 2

Modulus of Rupture (Bend Strength)

1,4-2,0 daN/cm

Tensile Strength, Transversal

0,6-0,9 daN/cm

Tensile Strength, Longitudinal

0,5-0,8 daN/cm

2

2

Dimensional Variation 23-32 ºC, 50-90 % HR

0,3%

Oxygen Index

26%

Tension Deformation at 10% (compression) Temperature Deformation (80ºC)

2

1,5-1,8 daN/cm

1,4 to 2,4 % (thickness)

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A synthetic comparison of the properties of pure cork agglomerates and those of its competitive materials can be found in Pfundstein et al. (2008).

Currently dominating the market of insulating materials for building construction, the ones that can be considered as the strongest competitors of pure cork agglomerates are40: 

Mineral Fibers (Glass and Rock);



Expanded Polystyrene (EPS);



Extruded Polystyrene (XPS);



Polyurethane Foams (PUR).

The following table [Fig. 4.34] gathers the comparative data analyzed and presented in this technical publication41.

Building Insulation Materials - Properties XPS Extruded Polystyrene

20 - 200

15 - 30

25 - 45

30 - 100

100 - 220

Thermal Conductivity W/(mK)

0.035 - 0.045

0.035 – 0.040

0.030 – 0.040

0.034 - 0.030

0.045 - 0.060

Specific Heat Capacity J/(KgK)

600 - 1000

1500

1300 - 1700

1400 - 1500

1700 - 2100

Maximum Service Temperature ºC (short-term)

250

100

100

250

180 - 200

Maximum Service Temperature ºC (long-term)

100 - 200

80 - 85

75

-30bis + 120

110 - 120

Compressive Stress kPa (at 10% of deformation)

15 - 80

60 - 200

150 - 700

100 - 500

100 - 200

Tensile Strength kPa (perpendicular to plane of board)

3.5 - 80

> 100

> 200

40

30 - 50

Density Kg/m3

PUR Polyurethane Foam

42

EPS Expanded Polystyrene

Properties

Materials_ MV Mineral Wool (Glass / Rock)

Considering the German market as a reference, Pfundstein et al. (2008: 20) presents an

40

ICB Insulation Cork Board

Figure 4.34

analysis of the market shares of the insulating materials in 2005, which reveals the following

Comparison of building

shares: mineral fibers – 54,6%; EPS – 30,5%; XPS – 5,8%; PUR – 4,9%; Others – 4,2%. IN total,

insulation materials

these materials represent about 96% of the market while the market share of pure cork

properties, according to

agglomerates is estimated to be about 0,1% (Pfundstein et al., 2008: 46).

Pfundstein et al. (2007).

When comparing Gil and Pfundstein et.al. tables, it is possible to notice some variation in the

41

values due to eventual differences in the methods and evaluation criteria (standards) that were followed. Although Gil had a more elaborate description about the pure cork agglomerate properties and behavior, Pfundstein et.al. defined a common framework to set the comparison between materials. For these reason, it was decided to kept both analysis without mixing them.

It was kept the ICB term to follow the book’s designation for pure cork agglomerate.

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By reading this table, it is possible to verify that pure cork agglomerates present a balanced performance when considering the overall set of analyzed goals. A detailed comparison with its competitive materials will be done next, when the materials’ applications in architecture are analyzed from a more practical point of view.

4.3.4 Products and Applications

When John T. Smith discovered the self‐agglomeration of cork by the end of the 19th century, he found an immediate application in the production of life‐ preservers, because the new material was lighter than raw cork. The envisioning of its insulating capabilities only came later by Messrs. Stone and Duryée. Acquiring the Smith’s patent rights, they started its industrial manufacturing in 1894 oriented towards the steam pipe covering business (Thomas, 1928: 31). An immediate interest by the United States Navy in this material pointed to the “real field of usefulness for Smiths’s Consolidated Cork – as an insulation material for cold surfaces” (Thomas, 1928: 31). In 1904, the American company Armstrong started in Pennsylvania the production of insulating cork materials, which became the standard insulating material for cold rooms and buildings for many years (Prentis Jr., 1950: 15). Today, it is the Portuguese company AMORIM the world largest producer of pure cork agglomerates, being the leading reference in the industry and in the market.

Products

Today, pure cork agglomerates are fabricated as boiled raw blocks, which, after their dimensional rectification, have the following dimensions43: 

Area: 1000 x 500 mm



Height: 10 – 300 mm

These dimensions can be different according to the fabricator and the country where the

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material is sold.

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The cutting of these raw blocks into different thicknesses originates the commercial products that are available in the market today. With a standard area of 1000x500mm, the different thicknesses can range from 10mm to the height of the original raw block. Formally, depending on the final proportion, these products can be understood as: 

Blocks



Boards

The recycling of those products through trituration gives origin to a third commercial product: 

Re‐granulate

In a recent past, there were also other products like tubes for covering pipes made in pure cork agglomerate, but they are not so common nowadays.

As discussed before, within the industrial manufacturing processes of pure cork agglomerates there are very few possibilities for introducing formal variation [Fig. 4.35]. At the same time, concerning the granulometry and density, the industry has reduced its regular manufacturing to materials with an average density of 120Kg/m3, and a granulometry between 4‐21mm.

Therefore, in the current market, there is no particular distinction between the type or application goal for the pure cork agglomerates. Products with such mean characteristics have demonstrated a good performance in serving thermal, acoustic and anti‐vibration purposes, and the choice of their thickness is usually explored to improve its behavior in any of these areas.

Nonetheless, specific densities can still be produced upon request.

Figure 4.35 Pure cork agglomerate products –rectangular boards with standard size and thickness.

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Concerning the re‐granulate, its density is around 70‐75 Kg/m3 (Gil, 1998: 221). In the market this product is sold with different granulometries, like 0‐ 3mm, 0‐10mm, 0‐15mm or 3‐15mm, stored in sacks with several dimensions.

From this overview, it is possible to argue that the standardization logic that rules the industrial manufacturing processes of pure cork agglomerates is a reality that is also extended to the commercialization area.

Applications

The main application of pure cork agglomerate products have been since its commercial origins as insulating materials. This fact has promoted its international denomination as Insulation Cork Board (ICB)44, targeting the following goals: 

Thermal



Acoustic



Anti‐vibration

Besides the insulation of cold storage rooms, the building construction industry has been a fertile ground for the application of this material. Due to the complexity of buildings and its requirements, pure cork agglomerates have been used in many different situations. In an analysis about insulating materials for architecture, Pfundstein et al. (2008: 18, 19) acknowledges the following set of recommended standard applications for pure cork agglomerates [Fig. 4.36]. With the contribution of the technical recommendations by cork producers, Gil (1998: 197) extends the range of applications by introducing some diversification in the detailing solutions.

[Fig. 4.37]

As said before, considering its disciplinary purposes, this research prefers to name this

44

material as “pure cork agglomerate” in order to keep open the suggestion for other uses rather than simply the traditional role of insulating.

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199

Figure 4.36 Conventional recommended applications for using pure

External insulation to suspended floor or roof, protected from the weather, insulation below roof covering

External insulation to suspended floor or roof, Protected from the weather, Insulation below waterproofing

Floor and Roof

Insulation between rafters, Double-skin roof, accessible but non-trafficked Topmost suspended flooor

Internal insulation to suspended floor (underside) or roof, Insulation below rafters/structure, Suspended ceiling, etc.

Internal insulation to suspended or ground floor (top side) below screed, Without sound insulation requirements

External insulation to wall, behind cladding

External insulation to wall, behind render (plinth insulation, thermal bridge insulation)

Cavity insulation to double-leaf walls Wall Insulation to timber-frame and timber-panel forms of construction

Internal insulation to wall

Insulation to separating walls

cork agglomerate products in architecture.

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Figure 4.37

Applications of pure cork

construction.

agglomerate in building

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By analyzing the previous figures, it is possible to verify that the diversity of the scenarios where pure cork agglomerates have been traditionally used in building construction can be reduced to one of these two situations:



Hidden applications Most of the insulating details considers cork as an infill material that has no visual presence in the outer or inner space.

In this scenario, pure cork agglomerates just play the role of insulating material;



Visible applications When used as a finishing material in building construction, it solely happens in interior conditions; In this scenario, pure cork agglomerates play the simultaneous role of insulating and decorative material, or just decorative.

Comparative Analysis

Complementing the scientific and technical data presented in the previous point, it is now important to add some comparative comments, from a practical perspective, between pure cork agglomerates and its most competitive materials in the market ‐ Mineral Fibers, EPS, XPS and PUR. The following analysis intends thus to identify some of the pros and cons that can influence the selection of materials in architecture.



Forms of supply The formats in which products are offered in the market is a crucial aspect for architects, because their application is constrained by the formal and geometric nature of their building designs. The following table summarizes the most common forms of supply for the different materials. [Fig. 4.38]

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Building Insulation Materials – Forms Of Supply

Forms

Materials_ MW Mineral Wool (Glass / Rock)

Boards

●

Rolls

●

EPS Expanded Polystyrene

●

XPS Extruded Polystyrene

PUR Polyurethane Foam

●

●

●

●

In-Situ Foam Granules

ICB Insulation Cork Board

●

●

●

Considering that most building construction works are characterized by their planar and orthogonal geometries, all these insulating materials are equally suitable for application. However, facing design solutions with complex geometries, like many of the contemporary iconic buildings, insulating materials must be easily adapted to the shape and form of those buildings. In this context, mineral wools, especially glass wool supplied in flexible formats, and polyurethane foam, which can be projected in‐situ directly to the buildings’ surface independently of its geometry, present clear advantages facing the more rigid boards‐format in which the other materials are supplied.

For the insulation of free‐form buildings and structures, this can be a decisive aspect.



Insulating performance All the materials in discussion are considered as thermal insulators.

However, as seen before in the materials’ technical data, pure cork agglomerates are those with the highest thermal conductivity, mostly because of its superior density. However, their highest specific heat capacity can sustain a higher accumulation of heat and cold. Leading to a very low thermal diffusion, it is claimed that this fact can draw an overall thermal insulating performance comparable to that of its lighter competitors.

Concerning acoustics, density and porosity are determinant factors for sound insulation and sound absorption behaviors. In this context, mineral wools, presented in different densities and formats, can be explored solely or in combination, to provide excellent acoustic insulating capabilities. Because cork is denser than its pairs and it

Figure 4.38 Forms of supply of building insulation materials, based on Pfundtsein et al. (2007: 20).

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has some porosity, it is also considered as a good acoustic insulating material by itself, which does not happen with EPS, XPS and PUR.

Finally, concerning anti‐vibration purposes, pure cork agglomerates are very good insulating materials, due to their resilience and poisson coefficient. EPS, XPS and PUR are also very good energy absorption materials, which is clearly justified by their extensive use as packaging materials.

As an overall remark, among all the materials, pure cork agglomerates are perhaps the ones that can better satisfy all the three building insulating goals by itself solely. To accomplish the same performance, the other materials would have to be combined with other elements to fulfill the same goals.



Construction Details Considering the insulating constructive details, EPS, XPS and PUR are presented as flexible solutions that can be implemented also in contact with soil and outside of waterproofing layers because of their imperviousness45. These kind of situations must be avoided when using fibrous materials like mineral wools, because they are more vulnerable. Regarding pure cork agglomerates, their porosity tend to accumulate some moisture or water in their surface, which can reduce its insulating performance. From the technical point of view, this aspect could be overcome by increasing the thickness of the boards, because after an initial layer of infiltration, the moisture and water are contained, as explained before.

Among all these materials, glass wool is the one that should not be used in situations subjective to compressive loads. All the other materials can be supplied in high density formats that can take the load pressures.

The use of EPS in such conditions can imply the application of an hydrophobic treatment. XPS

45

is considered as the unique material that can be used submerged in water without any protective layer.

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Fire resistance Based on Pfundstein et al. (2008), the following table resumes the standard classification of the fire behavior of building insulating materials. [Fig. 4.39]

Building Insulation Materials – Reaction To Fire

Forms

Materials_ MW Mineral Wool (Glass / Rock)

Reaction to Fire Building Material Class A1, A2 – Incombustible

A2 (glass) A1 (rock) ;

EPS Expanded Polystyrene B1

XPS Extruded Polystyrene

PUR Polyurethane Foam

B1

ICB Insulation Cork Board

B1, B2

B2

B1 – Not ready flammable ; B2 - Flammable

From this classification, mineral wools are definitely the best

Figure 4.39

materials, followed by EPS, XPS and PUR. Although the reaction to

Reaction to fire classification

fire’s classification of pure cork agglomerates is lower than that of

materials.

of building insulation

polystyrene materials, the personal observation of a comparative fire testing conducted in the AMORIM factory makes very difficult to understand the reasons supporting such an evaluation. [Fig. 4.40]

Figure 4.40 In this fire test carried out at the AMORIM, a 40 mm XPS board and a 40 mm pure cork agglomerate board were exposed to a 700º C flame. In 13 seconds, the XPS was fused and perforated by the fire, losing all its formal resistance and realizing a lot of dark and toxic smoke. After 5 minutes of exposure to the flame, the temperature in the opposite surface had barely changed. It was around 25ºC while

releasing a few non‐toxic smoke. In these tests, that are regularly carried at AMORIM,

the weakest records show

boards have been perforated

that pure cork agglomerate by the flame only after 50 minutes of exposure, while in others they kept intact for more than 2 hours.

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Durability All these materials are considered to have a long longevity. However, it should be noticed that EPS, XPS and PUR are vulnerable to the contact with other products, like chemical agents. On the contrary, pure cork agglomerates are very resistant in such conditions, and its wider use temperatures make it a good material for facing extremely cold or hot conditions. When exposed to the sunlight, the color of pure cork agglomerates becomes lighter but it does not compromises its performance or durability. In a different way, EPS, XPS and PUR when exposed to ultraviolet radiation suffer discoloration and some alterations in its resistant capabilities (Pfundstein, 2008: 34‐39).



Decoration Among the recommended standard construction details, none of them considered the visual appearance of the insulating materials. In this aspect, pure cork agglomerates have been used regularly as a finishing material for covering interior walls and ceilings.

Furthermore, despite this inner use, some recent innovative examples in architecture, which will be discussed in the next point, have used pure cork agglomerates as an external cladding material.

In any case, adding to its insulating performance, this material can simultaneously serve aesthetic goals. In this context, the visual appearance of any of its competitors was never considered as a possible decorative and finishing material. This can be related to some durability problems but also to their specific artificial material qualities, which eventually do not appeal for human fruition.



Maintenance The demand for maintenance is a very important feature when considering a material for finishing purposes, mainly due to the economic implications overtime that it can bring. As explained before, its durability and natural properties, make pure cork agglomerates a finishing material that demands no maintenance during the building’s life cycle, in both interior and exterior conditions. If any pure cork agglomerate panel or block is damaged by any reason, like due to mechanical degradation, it can be replaced by a new one. By sending the old one for recycling, this process of

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material substitution is easy, ecological and sustainable. Because its competitors do not fulfill this application, they are not brought into this discussion.



Ecologic and Sustainable aspects Being 100% natural, fully recyclable, and reusable materials, pure cork agglomerates are ecological products inscribed in a renewable production and life cycle. On the contrary, mineral wools, EPS, XPS and PUR are only partially recyclable. Due to their composition, these last three materials, when exposed to fire, release toxic fumes.

Also, the use of mineral wools, especially glass wool, must be carried with some caution, due to some unhealthy risks. Finally, a graphic comparison between these materials concerning many sustainable parameters, like the Primary Energy Input (PEI) or Global Warming Potential (GWP), is presented by Hegger et al. (2006: 141). In this study, it is possible to verify the clear supremacy of pure cork granulate, which affirms its unvaluable sustainable dimension.



Price Price is one of the factors that has a greater influence on architects and clients’ material choices. In a market survey developed in 200946 it was possible to verify that mineral wools and EPS are the cheapest insulating materials, while pure cork agglomerates are the most expensive ones. Considering price variations between producers, the cost per m2 of a pure cork agglomerate board can reach 2,5 times the price of mineral wool and EPS boards with a similar thickness and insulating behavior. Such higher price of pure cork agglomerates can be justified by several reasons. Probably the most decisive one is the fact that it is a 100% natural material and its raw material, cork, is obtained from a slow production process – the cultivation and harvesting of the cork oak forest – that is very concentrated in a specific and small part of the planet. Other materials can be industrially produced anywhere and with a larger production output, which also reduces transportation costs.

However, pure cork agglomerates have some qualities and advantages that can favor its preference over other materials despite

This market survey considered the 2009 prices of products commercialized by the following

46

Portuguese material companies: AMORIM, SOTECNISOL, ISOSFER and ESFEROVITE.

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its more expensive cost. Challenging the perception of its price, the following factors should be highlighted: a) being a 100% natural and ecological material constitutes an added value today, which makes it a special ‐exquisite‐ material; b) its durability and zero maintenance over time makes the material investment become diluted over time; c) the possibility for accomplishing several functions with a singular material foster a reduction of materials and construction layers in building construction, and a simplification of the building installation works, which can bring benefits at the cost level.

4.3.5 Innovative References

Pure cork agglomerate is a very complete material from the performative point of view. One way of taking full advantage of this material consist in searching for architectural applications where it can play several functional roles at once. The better this versatile potential is explored in practice, the greater the advantages of pure cork agglomerates over their competitive materials, and the smaller become some of the disadvantages (e.g., price), which currently impedes it to have a more significant presence in current building construction.

The beginning of the present century was the starting point for rethinking the use of this material beyond its traditional applications in hidden or interior situations. At the EXPO 2000 World’s Fair held in Hannover, there was an revealing coincidence. Both the Portuguese architect Álvaro Siza and the Spanish architects Cruz & Ortiz decided to use cork to cover the facades of the Pavilions they had designed for their countries. Within an event

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dedicated to the relation “Humankind‐Nature–Technology”, such material selection seemed perfect to illustrate the theme47.

However, the architects followed different material strategies. On the one hand, Siza opted for using pure cork agglomerate blocks, produced by the existing technology, and sharply pointed a new use for it. On the other hand, Cruz & Ortiz decided to design a new composite product, made by an interior layer of 70mm thick cork agglomerate, which was glued with a polyurethane resins to an exterior layer of a 20mm thick natural cork48. Although in different ways, these innovative works have contributed for expanding the range of cork applications in architecture. Beyond its invisible insulating properties, Siza and Cruz & Ortiz foresaw the interest of using cork for defining the visual appearance of a building, thereby elevating it to an exterior finishing material.

By employing cork, Siza’s Pavilion had a decisive influence on the current dissertation. The success of his pioneering work, led some other architects to follow his innovative example. A recently completed singular house in Portugal, designed by the studio Arquitectos Anónimos, is another remarkable work where pure cork agglomerates were used not only to cover the building external walls but also its roof. Finally, it is no less important to mention that Siza, himself, decided to repeat his material choice in another recently finished building, the Quinta do Portal Winery in the Douro river in Portugal.

Thus, it is essential to investigate these references to know more about this new use of pure cork agglomerates in architecture, while envisioning eventual opportunities for digital innovation.

One of the most notable pavilions of the EXPO 2000 was the Japanese pavilion designed by

47

Shigeru Ban with the consultancy of Frei Oto, where he explored a structural grid made by paper tubes that supported a recyclable paper membrane. In this work, Shigeru Ban followed a similar attitude as Siza and Cruz & Ortiz, by deciding to rethink the application of an existing ecological material.

This technical solution is explained in the website of the General Council of the Technical

48

Architects of Spain (http://www.arquitectura‐tecnica.com/ARTCERCH553.htm, consulted in September 2009)

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Álvaro Siza : The Portuguese Pavilion for the EXPO 2000 Hannover, Germany, 2000

Figure 4.41 General view of the Portuguese Pavilion in Coimbra, Portugal.

The Portuguese Pavilion for the EXPO 2000 was conceived as a pre‐ fabricated structure that should be dismounted after the World Fair and re‐ assembled in Coimbra, Portugal, afterwards [Fig. 4.41]. The conceptual origins of this building are linked to a simultaneous interest of representing Portugal in a World Fair while corresponding to its theme call. The solution for this equation was found by Álvaro Siza in cork, given its economic and social importance for the country and its remarkable ecological and sustainable value. In contacts with the cork producers AMORIM Isolamentos, Siza questioned the possibility of using pure cork agglomerate in the exterior of the building. According to Carlos Manuel, the company’s general manager, this was first time that such a solution was proposed49. So, they had to carry some investigation and technical tests to evaluate the efficiency of such solution. By increasing the thickness and density of the material, it was concluded that optimal insulation goals could be achieved, independently of the material direct exposure to the weather conditions. At the same time, the durability of the material was estimated to long in good use conditions for a period of 30 years time. Being a temporary event, this condition was more than sufficient to move forward with Siza’s solution.

From the technical research, high density panels with a thickness of 80 mm were considered sufficient to accomplish the insulating demands expected for the cold climate in Hannover. However, the tectonic tradition of architecture suggest that the particular nature of a building material tends to call for a specific application that synthesizes their technical functionality This information was gather in personal conversations with Carlos Manuel at AMORIM

49

Isolamentos, that occurred in several moments during this dissertation.

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with their expressive and poetic potential. Rooted to this way of feeling, which merges scientific and artistic endeavors, Siza felt compelled to devised a structural metaphor for using pure cork agglomerates. According to Nuno Graça Moura50, the constructive solution for a facade with this material should express a strong masonry effect and not a superficial cladding appearance. This tectonic intention led to the use of blocks thicker than the required from the insulating point of view. To accentuate this poetic expression, unique blocks in “L” shape were specially manufactured to solve the building corners. With this constructive detail, Siza conveyed the perception that pure cork agglomerate blocks were even thicker than what they were in reality. [Fig. 4.42]

Technically, with the exception of the corners, the facade was thus built in 200kg/m3 density pure cork agglomerate, with the standard size of 1000x250x150mm. Fabricated by current industrial processes in Portugal, the perimeter of each block was then cut to define a dry interlocking assembly connection between blocks, which were fixed to a continuous surface of galvanized steel panels. Behind this metal surface, a ventilation gap helped the insulation performance and hide some technical and mechanical installations. From the exterior, the Pavilion’s facade was characterized by a regular tiling of repetitive pure cork agglomerate blocks. However, the free form geometry of the roof, required the cutting of some cork blocks in‐situ, to fit them to the desired curved geometry51.

During the building’s life at the EXPO 2000, the unusual material’s appearance and odor attracted the curiosity of the Pavilion visitors. While waiting to enter in the line next to the building, they felt compelled to touch the cork facade, which provoke some disintegration in a few blocks, especially caused by children scratching. Thus, during the Fair, a couple of blocks had to be sent for recycling, being replaced by new ones. What is interesting here is that those actions were not caused by vandalism, but by the curiosity and empathy engendered by the pure cork agglomerate used as a finishing material [Fig. 4.43]

Nuno Graça Moura was the project architect from Siza’s office that worked in the Portuguese

50

Pavilion project for the EXPO 2000. A personal conversation occurred in 2004, was enlighten to understand better the ideas behind the use of cork in this building.

The development of this roof with such a complex geometry was done in collaboration with

51

the Ove Arup’s engineer Cecil Balmond.

Figure 4.42 Building corner showing the expressive detail suggesting the use of very thick pure cork agglomerate blocks in the facade.

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With the Fair’s end, the insulating performance of Siza’s constructive solution

Figure 4.43

was confirmed. Indeed, the Portuguese Pavilion was the only building that

South view of the Portuguese

did not use air conditioning. With its dismantling, the pure cork agglomerates demonstrated to be in very good conditions, ready to be reused. At the same time, it was observed that the facades that were more exposed to direct sun light suffered some color change. Over time, the brown color of those pure cork agglomerate blocks became lighter, but this alteration did not affect their performative behavior.

Thus, considering that they were exposed to harsh climate conditions during the Fair period, with snow and cold temperatures, AMORIM specialists concluded that, indeed, they could not predict a limit to the durability of the material, because it could be much more than the initially estimated 30 years.

After Hannover, the Pavilion was rebuilt in Coimbra, Portugal, and has stayed with the cork blocks exhibiting very good conditions.

Pavilion in Coimbra, Portugal.

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Reference 2 : Arquitectos Anónimos: The Cork House Esposende, Portugal, 2008

Completed in 2007, the Cork House is a singular house that was carefully

Figure 4.44

conceived to fit a very tight budget and generate a consensus among a group

General view of the Cork House.

of ten family members. Therefore, according to the author, design decisions were taken very pragmatically, which did not impede one to achieve a formal and materially distinctive overall solution (Arquitectos Anónimos 2009).

Motivated by ecological, performative and economic goals, Arquitectos Anónimos became interested in pure cork agglomerate and developed a particular conceptual approach to its application in the exterior. In this house, they decided to extend its use to encompass the roof situation. Instead of covering just its vertical facades, the whole building was involved in a continuous cork skin, which established a dialectic relationship with the landscape qualities and the agricultural fields of its surroundings.

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Figure 4.45 View of the house showing the material continuity between facade plans and roof.

Figure 4.46 Cork panels tiling, organized in a repetitive pattern.

Besides generating an innovative material expression, the Arquitectos Anónimos intention brought some constructive challenges, which were cleverly solved. Ordinary built‐up walls and roof structures were covered with a textile skin to guarantee the imperviousness of the building. Then, glued to it, a set of very thin aluminum profiles created a support structure onto which pure cork agglomerate blocks could be directly glued. In this project, the blocks had the standard dimension of 1000x500mm with 150

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mm thickness and, unlike in the Portuguese Pavilion, they did not have any joint detail between them.

The technical solutions adopted with the pure cork agglomerate contributed decisively for the economy of the project, mainly due to the following reasons: 

with a single material, decorative (finishing) and insulating demands were accomplished;



by reducing the number of building materials and layers needed, the construction process became simpler;



the exploration of gluing methods facilitated the assemblage process;



the use of standard shape blocks without any geometric connections avoided extra manufacturing works and its inherent additional costs;

Furthermore, the fact that pure cork agglomerate does not need maintenance will bring a considerable economic benefit for the owners overtime. Also in the end of the building’s life, the whole facade can be fully recovered for recycling purposes. In this context, it seems possible to defend that the more expensive cost of pure cork agglomerates compared to other materials can become a relative issue, considering the whole set of arguments just described.

With the Cork House and its continuous natural skin, the great potential that pure cork agglomerate can have for exterior applications in building construction seems confirmed. Aesthetic, performative and ecological motivations can thus converge into a single material, in a exemplary way.

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CONCLUSION

Considering the degree of innovation achieved in other traditional materials through the use of digital technologies, this chapter started with the idea that cork could be an interesting case‐study material for this dissertation. By making literature and industry surveys, it was possible to learn about cork that: 

it is a natural and ecological material that is extracted from a tree without implying cutting it down;



it has been a useful material for man since the antiquity, giving origin to a highly diversified range of products and applications, from the most banal and crude, to the most sophisticated and technological;



it remarkably combines a wide range of interesting properties that make it a singular material from the performative point of view;



its productive and manufacturing industry is concentrated today in a few countries of the West Mediterranean area, particularly in Portugal and Spain;



it has been mostly known for its application in cork‐stoppers, which constitutes the great core of its industry and commerce, but it also had a persistent historical relation with the field of building construction, especially in the last 100 years;

This overview of cork, made it clear that it is an important material for the present and the future, and, consequently, interesting for this research. Its relevant role can be perceived simultaneously at two levels: 

on a local scale ‐ cork has a strong economic and social importance for the country of this dissertation, being the unique industry in which Portugal is a world leader today;



on a global level – together with its overall production cycle, cork has a priceless ecological value, which is of great interest for the sustainable challenges the world is facing nowadays;

Considering the diversity of existing cork products with potential for building construction, it was necessary to focus the attention on one product and thus pure cork agglomerate was initially selected. Supporting this preference, a

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set of arguments concerning its architectural, ecological and research potential were presented and discussed, leading to discard other more refined products (i.e., compound cork agglomerate and rubber cork). From this analysis, pure cork agglomerate appeared to be a material with a great potential for architecture. It involved a series of positive and confirmed qualities but also unknown and risky ones, which were perceived by this dissertation not as problems, but as opportunities for innovation.

Thus, pure cork agglomerate was subjected to a more in‐depth study, covering its production process, properties, products and applications.

Among other observations, this investigation revealed that: 

current production methods are based on a chain of mechanical technologies, which are based on repetitive procedures and standardized fabrication;



resulting from a self‐agglomeration process free from any adhesive product, pure cork agglomerates are 100% natural, ecological and recyclable cork materials that combines a wide range of interesting properties;



as a result of the few possibilities for variation allowed by the existing chain of manufacturing processes, pure cork agglomerate products are commercialized in standard sizes and densities with flat and orthogonal geometries;



its current uses in building construction are mainly driven by the traditional understanding of this product as an insulating material, and they can be resumed to hidden or indoors applications.



Among its insulating material competitors, pure cork agglomerate may not the best material in some of the evaluation categories, but, when considering them all, it seems to be the one revealing the highest and most balanced performance, besides its remarkable ecological value.

However, breaking cultural and technical barriers, recent years witnessed the emergence of a new field of application for pure cork agglomerate in architecture. The Álvaro Siza’s Portuguese Pavilion at the EXPO 2000 and the fresh Arquitectos Anónimos’ Cork House are innovative built works that successfully demonstrate the material’s possibility for external facade applications. In a curious way, these examples could establish a direct reference to much older uses of cork in building construction. Like the

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Capuchos Convent showed with its use of raw cork, both the Portuguese Pavilion and the Cork House revealed that the great potential of cork relies on its unique convergence of properties and functions, which is underestimated in the traditional applications and current commercial strategies.

Analyzing the market, I argue that as far as functional interest in pure cork agglomerate is reduced, the advantages its competitors are increased. On the contrary, the simultaneous exploration of its capabilities, like decorative, insulating, and exterior protection, allied to its ecological and recyclable nature, makes pure cork agglomerate an exceptional and unique material.

With this added value, subjacent economic disadvantages can become less relevant, as those built works can demonstrate.

In a moment when the facade is a fertile territory for architectural experimentation and representation, the possibility of defining the buildings’ visual appearance with pure cork agglomerate seems to be one of the greatest challenges one can face in developing architectural applications for this material today. However, it is important to look further. To match current architectural interests, design limitations imposed by current production processes rooted on standardization principles must be overcome.

Like in other materials industries, research into the possibility of using digital technologies for the manufacturing of pure cork agglomerate is a imperative step for the reinforcement of its competitiveness and attractiveness. Opening new formal and customization possibilities could lead to interesting design applications for using this material in visible condition, both at the aesthetic and performative level. Besides architecture, the cork industry can also benefit from the development of applications of the material, by expanding market alternatives beyond the production of cork‐stoppers.

The following graphic summarizes this chapter’s research and the hypothesis it has raised. [Fig. 4.47]

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Figure 4.47

Promising Examples

Diagram suggesting the hypothesis for innovating the

application of pure cork agglomerate in architecture through the use of CAD/CAM

technologies.

Traditional Applications

Innovative Applications

● Hidden

● Visible – exterior + interior CAD/CAM Technologies

● Visible – interior

● Custom contours + textures

● Flat + Orthogonal shape

● Freeform (3D)

● Repetitive patterns

● Variable patterns

Convergence of Properties

The strategy for such innovation possibilities, is inspired by what have

Figure 4.48

happened in the world of fabrication and architecture with other traditional

Updating the diagram of Fig.

materials, as observed in Chapter 2. Considering this, it is thus legitimate and

hypothesis on cork

pertinent to ask about what are the possibilities for rethinking cork through

2.35, for including the innovation.

the use of CAD/CAM technologies [Fig. 4.48].

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REFERENCES

References that are not mentioned in this chapter’s text belong to the credits of the images used, and are cited in the “Illustration Credits” section of this thesis.

(1)

AMORIM (2006): Relatório de Sustentabilidade, Corticeira AMORIM S.G.P.S., S.A., Mozelos.

(2)

APCOR (2006): Cork as a Building Material, Associação Portuguesa da Cortiça, Santa Maria de Lamas.

(3)

APCOR (2009): APCOR 2009 Yearbook, Associação Portuguesa da Cortiça, Santa Maria de Lamas.

(4)

Aronson, J., Pereira, J.S. and Pausas, J.G. (2009): Cork Oak Woodlands on the Edge. Ecology, Adaptive Management and Restoration, Island Press, Washington, DC.

(5)

Bergen, J.T. (Ed.) (1960): Viscoelasticity. Phenomenological Aspects, Academic Press, New York.

(6)

Campos, A.L. (2009): Cortiça. Do Sobreiro à Ciência de Ponta, National Geographic Portugal, N. 96, March 2009 (pp. 2–17).

(7)

Cooke, G.B. (1942): Cork and Cork Products. The History, Source, Properties and Uses of Corkwood, Crown Cork and Seal Company Inc.

(8)

Cooke, G.B. (1961): Cork and The Cork Tree, Pergamon Press, New York.

(9)

Cowan, H.J.; Smith, P.R. (1988): The Science and Technology of Building Materials, Van Nostrand Reinhold Company, New York.

(10) Da Veiga, J. & Ferreira, P. (2005): “Smart and Nano Materials in Architecture”, in Proceedings of the 2005 ACADIA Conference (pp.

58‐67), Savannah, Georgia.

(11) Diderot, D. (1993): A Diderot Pictorial Encyclopedia of Trades and Industry Vol II, Dover Publications, New York.

(12) Farrelly, L. (2009): Construction + Materiality, AVA Publishing, London.

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(13) Faubel, A.L. (1941): Cork and the American Cork Industry, The Cork Institute of America.

(14) Fernandez, J. (2006): Material Architecture, Architectural Press, Oxford.

(15) Fortes, M.A., Rosa, M.E. and Pereira, H. (Eds.) (2004): A Cortiça, IST Press, Lisbon.

(16) Fortes, M.A. and Ferreira, P.J. (Eds.) (2003): Materiais 2000, IST Press, Lisbon.

(17) Gaspar, N.M. (2005): O Convento dos Capuchos da Serra de Sintra: Percurso Histórico e Guia Interpretativo, VoxGo, Cacém.

(18) Gibson, L.J. and Ashby, M. (2001): Cellular Solids. Structure and Properties, 2nd Edition, Cambridge University Press, Cambridge, UK (19) Gil, L. (1998): Cortiça. Produção, Tecnologia e Aplicação, INETI, Lisbon.

(20) Gil, L. (2005a): Cortiça: da Produção à Aplicação, Câmara Municipal do Seixal.

(21) Gil, L. (2005b): “Cortiça” in Maria Montemor et al. (Eds.), Materiais de Construção ­ Guia de Utilização (pp. 96‐127), Loja da Imagem, Lisbon.

(22) Gonçalves, J., Amaro, A., Gomes, E., Gaspar, C. and Matos, C. (2005): A Utilização e Valorização da Propriedade Industrial no Sector da Cortiça, Instituto Nacional da Propriedade Industrial, Lisbon.

(23) Hegger, M., Auch­Schwelk, V., Fuchs, M. & Rosenkranz, T. (2006): Construction Materials Manual, Birkhauser, Basel.

(24) Hegger, M., Drexler, H. & Zeumer, M. (2007): Materials, Birkhauser, Basel.

(25) Hugues, T., Steiger, L. and Weber, J. (2007): Construcción con Madera, DETAIL Praxis, Gustavo Gili, Barcelona.

(26) Lefteri, C. (2005): Wood. Materials for Inspirational Design, RotoVision, London.

(27) Oliveira, M.A. and Oliveira L. (2000): The Cork, Corticeira AMORIM S.G.P.S..

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(28) Pereira, H. (2007): Cork: Biology, Production and Uses, Elsevier, Amsterdam.

(29) Pfundstein, M., Gellert, R., Spitzner, M.H. and Rudolph, A. (2008): Insulating Materials. Principles, Materials Applications, DETAIL Practice series, Birkhauser, Basel.

(30) Prentis Jr., H.W. (1950): Thomas Morton Armstrong (1836­1908).

Pioneer in Cork, The Newcomen Society in North America, New York.

(31) Salvador, S. (2001): Inovação de Produtos Ecológicos em Cortiça, Instituto Superior Técnico, Unpublished Document.

(32) Santos, C.O. (2002): O Livro da Cortiça, 4th Edition, Museu da Cortiça, Lisboa.

(33) Silva, S. P., Sabino, M. A., Fernandes, E. M., Correlo, V. M., Boesel, L. F. and Reis, R. L. (2005): “Cork: Properties, Capabilities and Applications”, in International Materials Review, Vol. 50, No.6, December 2005 (pp. 345‐362), Maney Publishing.

(34) Stecher, G.E. (1914): Cork: Its Origin and Industrial Uses, Van NOstrand Reinhold, New York.

(35) Thomas, P.E. (1928): Cork Insulation, Nickerson & Collins Co., Chicago.

(36) Zapata, S., Parejo, F.M.., Branco, A., Gutierrez, M., Blanco, J., Piazzetta, R. and Voth, A. (2009): “Manufacture and Trade of Cork Products: an International Perspective” in J. Aronson, et al. (Eds.), Cork Oak Woodlands on the Edge. Ecology, Adaptive Management and Restoration, Island Press, Washington, DC.

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5.1

INTRODUCTION

As seen in the previous chapter, the industrial production of pure cork agglomerate products is ruled by mass production processes based on standardization. As a result, commercial products for building construction offer very few and basic aesthetic and formal options. Any deviation to such possibilities is usually achieved by means of additional manual labor, which necessarily introduces new precision, cost and time related issues. Thus, despite its intrinsic valuable material properties, the potential of pure cork agglomerate products to match many of the current design interests in architecture still remain to be explored in today’s information age. Although a few built examples have already uncovered its potential as an external facade material, the unknown possibility for geometric customization with CAD/CAM technologies, is still preventing this material to address more sophisticated formal, ornamental and performative design strategies.

Departing from a simple example, it is possible to realize the limitations of such standardized condition. For instance, in both Álvaro Siza’s and Arquitectos Anónimos’ buildings, standard blocks had to be individually cut for adjusting them to the non‐orthogonal boundaries of the facade. Because this condition was anticipated in the design phase (i.e., it is drawn), such

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situations could benefit from the introduction of CAD/CAM processes at least in two ways. On one hand, the production of the adjusted pieces could have been directly fabricated from the CAD drawings, increasing the levels of precision and speed. On the other hand, knowing the possibility for 2D shape customization, eventually, a different cladding pattern could have been explored where, for instance, the notion of the adjusted piece would be blurred [Fig 5.01].

Figure 5.01 Comparison between patterning possibilities supported by mass production (top) and mass‐ customization (bottom) approaches.

Although many other conceptual influences in the design could be easily formulated, this example clearly demonstrates that the relevance of using CAD/CAM technologies with pure cork agglomerate could not only bring efficiency in current applications, but also could trigger designer’s creativity for exploiting new innovative uses. Although this aspect is intimately linked to architect’s expectations and desires, it also has the potential to raise an important commercial dimension that should not be ignored by the cork industry.

Thus, it becomes pertinent to research the potential of digital technologies to rethink the use of pure cork agglomerates in architecture. Targeting the emerging field of visible building applications, where it exceptionally plays several roles at once, this chapter intends to investigate new aesthetic and geometric possibilities for using this material. Considering the digital design and manufacturing phases, the great challenge for working with this material fundamentally lays today in researching the later. Indeed, because current digital design techniques do not offer any representational limitations, the crucial aspect resides on the manufacturing side where both material and fabrication parameters can affect design intentions in many ways,

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constraining or stimulating them. By investigating this field, integrated design and fabrication strategies can be conveniently formulated by architects to take advantage of their imagination and the material’s potential.

In this context, the present chapter is dedicated to document a series of practical experiments with pure cork agglomerate carried out with digital manufacturing technologies. The underlying goal is the investigation of the possibility to overcome the aesthetic and formal limitations of current commercial products mentioned above, by challenging a greater degree of customization and geometric freedom. Pointing three material design characteristics or categories, the following table resumes the aesthetic and formal options currently available in the market and identifies emergent design challenges to be explored [Fig. 5.02]:

Pure Cork Agglomerate Products: Design Characterization Category

Commercial Products

Research Challenges

2D Shape

rectangular and straight contours

variable and curvilinear contours and perforations

Surface Texture

no texture and smooth finishing

customized finishing effects exploring materials’ depth

3D Form

Box volume type with constant thickness

production of freeform components

As point of departure, the present’s chapter research accepts the existing

Figure 5.02

industrial production processes and introduces an additional manufacturing

Table: design

stage in the end of the chain, based on CAD/CAM technologies. At this phase,

pure cork agglomerate

current final standard products are the raw materials for the production of new customized products [Fig. 5.03].

By exploring the integration of a post‐processing digital manufacturing phase, the resulting conclusions have the potential to be easily implemented in practice, because they do not require significant changes in the current industrial set‐ups. As a result, both architects and the industry could quickly benefit from such improvements.

characterization of current products.

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CURRENT INDUSTRIAL PROCESSES Granulation

Boiling

Finishing

Final Product

cutting, sawing…

Standard

Finishing

Final Product

CAD/CAM

cutting, sawing…

Standard

CNC Technology

THESIS RESEARCH

Granulation

Boiling

Final Product Free Form Customized

For this research, the Portuguese company AMORIM generously granted the

Figure 5.03

material used for testing. Pure cork agglomerate boards and blocks were

Comparative diagram

provided in different thicknesses and densities, to test them with different

processes for the production

between current industrial

fabrication processes. Considering the solid format of pure cork agglomerate

of pure cork agglomerate

products, the use of subtractive fabrication is immediately suggested. As

proposed by this thesis,

materials (top) with the one

these processes are the most commonly used in architecture for exploring

comprising the integration of

mass customization and geometric freedom with a wide range of materials, it

(bottom).

becomes pertinent to examine their appropriateness to work also with pure cork agglomerate. Considering their generic capabilities, the following subtractive fabrication processes were selected to conduct the experiments: 

CNC Laser‐Cutting



CNC Water‐Jet Cutting



CNC Milling

In this context, this chapter starts by describing the digital technologies and processes used, identifying some of their most important specific features.

Then, according to the material research interests and the technological framework described before, a series of CAD/CAM experiments were formulated and developed. The following table resumes the practical tests that were carried out organized by the research themes [Fig. 5.04].

CAD/CAM technologies

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Figure 5.04

List of CAD/CAM Experiments

Table: List of CAD/CAM experiments undertaken in

Name

this research.

3-Axis Milling

Water-Jet Cutting

Laser Cutting

Technologies

6.3 Preliminary Test

E.0.1 - Milling

6.4 2D Shape

E.1.1

Contour Geometry

●

●

●

E.1.2

Cutting Tolerance

●

●

●

E.1.3

Design Test: Clover Panel

●

●

●

E.2.1

Step Over Parameter

●

E.2.2

Step Down Parameter

●

E.2.3

Speed Parameters

●

E.2.4

Tool Geometry

●

E.2.5

Design Test: Waving Panel

●

E.3.1

Design Test: CorkStruct

●

E.3.2

Design Test: 3D Panel

●

E.4.1

Design Test: Cork Stoppers Panel

●

6.5 Surface Texture

6.6 3D Form

6.7 Other

●

Drawing from this experiments, the end of the chapter concludes about the opportunities and limitations of integrating a post‐processing CAD/CAM manufacturing phase based on subtractive fabrication in current industrial processes. At the same time, it reflects about future research avenues that were suggested from the knowledge acquired with the experiments done.

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TESTING CONDITIONS

The development of the CAD/CAM experiments were based in the exploration of specific digital design and manufacturing technologies, comprising the integrated use of CAD/CAM software and CNC fabrication machinery. Next, there is a brief description about the technological conditions that framed this research.

5.2.1 CAD/CAM software

Targeting the expansion of the material’s geometric possibilities, it was crucial the selection of a design software with representational capabilities that does not constraint the designer’s intentions.

As discussed before, Rhinoceros is one of the CAD programs that currently perform better such job, allowing to translate any imaginable form into a three dimensional digital model. For these experiments, the design information driving the various manufacturing experiments were conceived and described with Rhinoceros.

For communicating with the different CNC fabrication machines, Rhinoceros allowed for exporting the design data into the various formats required. In some tests, the CAD files were exported into IGES or DXF formats and were used by external CAM programs (e.g., MasterCAM and VisualMILL) for generating and post‐processing the manufacturing instructions. In other tests, a Rhinoceros plug‐in called RhinoCAM was also tested for doing the CAM programming without having to leave the design environment.

In the course of these experiments, all these CAD/CAM strategies have successfully dealt with the data, allowing the manufacturing experiments to be developed without any design constraint imposed by the CAD processes.

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5.2.2 CNC Fabrication Technologies

The CAD/CAM experiments were undertaken with CNC Laser Cutting, CNC Water‐Jet Cutting and CNC 3‐axis Milling fabrication technologies. To get access to these CNC fabrication machines, different companies and institutions were contacted for supporting such initiatives. Following, there is a brief description about the machines that were used to support this chapter’s research.

CNC Laser Cut

LASINDUSTRIA

Based in Oeiras, the Portuguese company LASINDUSTRIA supported the development of the experiments with their industrial CNC laser‐cutting machine [Fig. 5.05]. Usually employed for sheet metal cutting, this was the first time that their equipment was used for cutting pure cork agglomerate material. At their manufacturing shop, the tests were conducted by technicians who prepared the CAM files from the original CAD files, and operated the laser‐cutting machine.

Laser‐cutting processes have some particular features that distinguishes it from other processes. The fact that the cutting process occurs under thermal action makes not all materials suitable for being laser‐cut. For instance, cork competitors like XPS or EPS materials can melt and loose its structural integrity. For these reasons, there was an initial expectation about what would be the behavior of cork under laser‐cutting. Another interesting feature regards the fact that the laser beam has virtually no thickness. When looking for material optimization, this feature permits a tighter nesting of the cutting patterns on the raw material.

In laser‐cutting, the key fabrication parameters that must be negotiated to achieve the desired cutting quality and depth are:



the intensity of the laser



the speed of the laser head’s trajectory

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Combining these fabrication options, it is possible to explore engraving and

Figure 5.05

cutting effects on the materials.

The CNC laser cut machine at

of the laser head during the

LASINDUSTRIA (left). Detail cutting process (right).

CNC Water-Jet Cut

VETOR 3

Settled in Pero Pinheiro, the Portuguese company VETOR 3 supported the development of the CNC water‐jet experiments with pure cork agglomerate boards [Fig. 5.06]. Among many other cutting machines for marble stones, this company uses water‐jet technology mainly for producing pieces with irregular contours and openings. Being their first time cutting pure cork agglomerate, the experiments were driven by a specialist, who generated the CAM instructions from the original CAD files, and operated the machine.

In water‐jet cutting, an abrasive material is projected with a water‐jet for cutting thicken and hard materials. Unlike laser‐cutting, the water‐jet head has a small diameter, which should be taken into account in the design and manufacturing planning. At Vetor3, the head had a small 3mm diameter. To explore this process, it is yet important to work with materials that keep their structural integrity and volume in wet conditions.

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In water‐jet cutting, the main fabrication parameters that should be taken

Figure 5.06

into account are:

The CNC water‐jet cut machine at VETOR3 (left).



the water‐jet head diameter



the speed of the water‐jet head’s movement

during the cutting process



the power of the waterjet



the type and amount of abrasive

Detail of the water‐jet head (right).

Working with pure cork agglomerate under such conditions was thus a challenge to be investigated.

CNC 3-Axis Milling

IST-UTL

Part of the milling experiments of this research took advantage of the Mechanical Engineering laboratory facilities at the Instituto Superior Técnico in Lisbon [Fig. 5.07]. Faculty and research students from the department helped generating the CAM instructions and operating the milling machine, whose 3‐axis movements resulted from the combination of a Z‐axis displacement of the milling head, with X and Y axis movements of the machine bed.

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In this machine type, the tool has a revolving rotation at a high‐speed.

Figure 5.07

Moving along 3‐axis trajectories calculated from CAD surfaces and lines, it

The CNC milling machine at

removes material from a workpiece. In this process, the geometry of the mill

milling head and tool during

tool plays a decisive role. Ranging from small to large diameters, and from flat to spherical ends, this element influences the whole fabrication planning and process and, consequently, the finishing quality of the fabricated pieces.

Furthermore, when used for cutting operations, the thicknesses of the tool are an important aspect to take into consideration in the design and fabrication planning.

In this research, besides exploring different standard tools and fabrication parameters, it was decided to design and order the production of a specific milling tool to the Portuguese company FREZITE. This idea came by considering the physical characteristics of pure cork agglomerate material to achieve a higher optimization of the fabrication process and alternative material effects.

In CNC milling, the main fabrication parameters to be considered are the following: 

Tool path geometry



Step Over



Step Down (cutting depth)



Cutting speed



Milling tool geometry

IST‐UTL (left). Detail of the the milling process (right).

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By carefully negotiating these factors, the length of fabrication and the finishing quality of the materials can be conveniently controlled to efficiently negotiate budget constraints with design and material’s effect intentions.

CNC 3-Axis Milling

IAAC

The milling machine at IAAC in Barcelona, share similar features and principles like those of the one described above [Fig. 5.08]. The main differences are related with the dimensions of the working bed, and with the fact that it remains static during the operations.

The main parameters driving CNC milling operations with the machine at

Figure 5.08

IAAC continue to be the:

The CNC milling machine at



Tool path geometry



Step Over



Step Down (cutting depth)



Cutting speed



Milling tool geometry

IAAC (left). Detail of the milling head and tool during the milling process (right).

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EXPERIMENT: PRELIMINARY TEST

E.0.1 Milling

Goal The first practical CAD/CAM test was an initial milling test to get an immediate sense about the viability of going forward with digital subtractive manufacturing experiments with pure cork agglomerate. Due to the adhesive‐free granulate constitution of this material, there was an initial fear about its behavior and resistance under machining conditions. The forces produced by a revolving tool in motion against the material could be too strong for the natural cohesion of the granules and provoke its disaggregation. If this happened, it would automatically put an end in some of the hypothesis launched by this research.

Description This first test consisted in the design and milling of a double curved surface on a cork material stock using the CNC milling machine at the IST. By working with such geometry, one could test the resistance of the material as well as the interest of using CAD/CAM technologies to materialize irregular forms. Thus, a material stock with 300mm x 300mm x 66mm was manually prepared by gluing layers of pure cork agglomerate and compound cork. By using such composite material, one could test and compare the milling behavior of two different cork products. [Fig. 5.09]

Figure 5.09 The digital surface generated in Rhinoceros, and the stock material used for the milling experiment.

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CAD/CAM Process The 3D digital surface was designed in Rhinoceros and then exported for MasterCAM, where all the manufacturing instructions were conveniently defined. This set‐up specified the use of a 12mm diameter tool with a ball nose shape, and the programming of two consecutive milling operations. For quickly removing some superfluous material, there was an initial roughing cut following a step‐over of 8 mm. Then, to achieve a smoother surface, the finishing cut was reduced to 4 mm. [Fig. 5.10]

Figure 5.10 The milling tool used in the experiment, and images of the CAM simulation in MasterCAM, of the roughing

and smoothing cut.

One of the major difficulties faced in this experiment was holding the material stock in the machine. The need of using metal clamps prevented the machine of milling the whole top surface but, considering the goal of this initial test, this fact did not constitute a real problem. However, it alerted for the necessity of taking it into account in future experiments.

As a first experiment with this material the IST’s machine, the milling velocity was adjusted over time, in an attempt to optimize the whole fabrication process. For instance, by perceiving in‐loco the material behavior, the machining speed was incrementally increased while the material resistance and chip‐forming was carefully observed. [Fig. 5.11] Figure 5.11 The milling process, where it is possible to see how the block was fixed in the machine.

Results Despite the intrinsic difficulties of a first test, this experiment served to confirm an expected good behavior of the compound cork material parts.

Concerning the pure cork agglomerate ones, it served to verify its capacity

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for withstanding milling machining conditions without losing its overall structural integrity. Moreover, observing the roughing cut in progress, this material revealed a capacity to represent machined textures while, observing the finishing cut, it could also produce highly smooth textures where the tool path is well dissimulated. [Fig. 5.12]

Figure 5.12 Final fabricated part, where it is possible to observe the topographic ring pattern, emerging from milling across the different material layers.

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For such reasons, the success of this first experiment encouraged the pursuit of the practical research with pure cork agglomerate, as initially envisioned.

It was also interesting to check how the successive layers of the two different materials gave origin to an interesting topographic material and color effect, which can open other parallel research ideas in the future.

5.4

EXPERIMENTS: 2D SHAPE

E.1.1 Contour Geometry

Goal The Contour Geometry experiment examined the possibility for cutting pure cork agglomerate with irregular customized contours. The goal investigating the possibility for 2D shape customization by testing the efficiency of different CNC cutting technologies. This experiment thus attempted to evaluate the possibility to overcome the limited options currently available in the market, which are based on standard rectangular contours.

Test Description This experiment consisted in fabricating two kinds of irregular shapes out of a pure cork agglomerate board. To test different geometric conditions, one contour was based on straight lines and the other one was based on curved line. In both cases variable dimensions for each contour segment and different transition angles were considered for evaluating the efficiency of the cutting process. [Fig. 5.13]

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Figure 5.13 Original CAD drawing.

Carried out in different places, this experiment covered three different CNC cutting processes: 

laser‐cut (Lasindustria)



water‐jet cut (Vetor3)



milling machine (IAAC)

The material used in the tests were standard boards of pure cork agglomerate, with: 

thickness: 30 mm (laser + milling), 40 mm (water‐jet)



area: 1000 x 500 mm



density: 120 Kg/m3

CAD/CAM Process In laser‐cutting, the 30 mm thickness pure cork agglomerate board was placed over the machine table without any fixation devices. Because there is no contact between the cutting tool and the material, it was not expected the material to move during the fabrication process. However, the possibility of the laser power burn the material was a real concern that led specialized operator following very close the experiment. During the cutting process, there was some smoke release and some flames were visible, which were immediately contained by the material. Interestingly, due to its natural fire retardant properties, pure cork agglomerate avoided the propagation of the flame, allowing the laser cutting to continue its process fluidly. Perhaps the most relevant aspect emerging from this experiment, was the calibration of

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the laser power. On one hand, if it was too low, the laser could not cut through the material in one passage, especially in the areas where harder impurities existed. In such cases, a second laser passage would be necessary, but it would bring important time and cost consequences. On the other hand, if the power was too strong, the contour cutting quality would not be sharp enough in the edges because they ended up slightly burned. Trying to slow down the cutting velocity and keep low the laser power also did not prove to solve the problem. In this context, the material characteristics revealed to withstand a thermal cutting process, but the heterogeneity of its composition, containing harder impurities, created some difficulties for finding an optimum balance among the laser‐cutting parameters. [Fig. 5.14]

Figure 5.14 Laser‐cutting process.

In water‐jet cutting, the 40 mm thickness pure cork agglomerate board was placed on the table grid and locked with the help of some heavy marble pieces placed on its sides. Due to its lightness, the strength of the water‐jet cut could make the board move, so this was an easy way to solve the problem. The running of this fabrication process revealed some interesting observations. In the beginning, the water‐jet employed a small dose of abrasive but it became quickly evident that it was not necessary due to the material softness. This avoidance of abrasives, which are expensive, implies a reduction of the fabrication cost when compared with cutting other harder

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materials. At the same time, the easiness in which pure cork agglomerate was cut allowed testing the maximum cutting speed of the machine. Being about three times faster than in cutting marble, this possibility adds other important time and cost reduction possibilities. In any case, throughout the whole process, the water‐jet demonstrated to perfectly cut through the pieces. The only problem to highlight in this experiment was the fact that when cutting straight angles at high speed, the jet ended up rounded them.

By discussing this with the operator, it became evident that this should be a minor problem related with some CAM parameter missing in the programming, which was not possible to identify during the short period when this experiment was carried out. [Fig. 5.15]

Figure 5.15 Water‐jet‐cutting process.

In milling, the 30mm thickness pure cork agglomerate board was fixed on a wooden base by means of screws placed in the corners. This support structure was itself fixed on the table with some lateral fixture devices. Being one option among many possible others, this system offered a set of advantages for running some of the milling experiments.

On one hand, by having the wooden base permanently fixed on the machine table, the XYZ relative positioning of the milling tool was done just once time, right in the beginning. Then, by doing the same perforations in all pure cork

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agglomerate boards, the milling tests could run consecutively, replacing the milled board with a new one using the screws to position it. This process avoided losing considerable time resetting the machine and positioning new boards for each test.

On the other hand, the wooden base also protected the machine bed from being milled, which can accidentally happen in subtractive fabrication processes. Regarding the milling process, different cutting depths were tested until concluding that the 30mm thickness board could be cut in just one passage, by setting the tool to run at 32mm depth. However, due to the tool’s 8mm diameter, after cutting the pieces they became separated from the rest of the material and tended to move. At this moment it was important to carefully help fixing the piece with the hand to avoid machining interferences. Nonetheless, this manual intervention could be avoided if the vacuum system of the table for fixing materials was used. Another critical aspect realized in this experiment concerns the description of straight angles.

Because the milling tool is cylindrical, when it cuts a straight angle it becomes rounded and not angular, which is a design problem. This can be minimized or avoided by carefully planning the tool‐paths, making adjustments in the contour drawings or using tools with smaller diameters.

Finally, unlike the previous cutting processes, milling pure cork agglomerate board releases some waste material in the form of very small granules.

However, when the machine finds some harder impurity and releases it, it can drag together some attached cork granules and provoke some finishing imperfections. In the end, the quality of the cutting edges can be considered good and, moreover, it can still improve if higher density boards are used.

The geometric contour cutting possibilities are endless, but the problem with the straight angles must be taken into account. [Fig. 5.16]

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Figure 5.16 The milling process.

Results Besides the particular facts inherent to of each cutting technology, the following general conclusions may be highlighted: 

Unlike other materials, pure cork agglomerate can be cut with the three different subtractive fabrication technologies (e.g., thermal, abrasive and chip‐forming);



Laser‐cutting was the less‐efficient process to cut pure cork agglomerate. It was slow and the finishing quality was low;



Water‐jet cutting was the best process for cutting the material, as it was a clean, fast and precise process. Furthermore, the power of the water‐jet, and the fact that no abrasive was used, allowed foreseeing the possibility for easily cutting thicker boards in just a one passage;



Although it was the fastest process, cutting pure cork agglomerate with the milling machine wasted some material, which does not make it the most clean process for cutting. However, this was important to investigate because if other fabrication operations are also meant to be done over the material (e.g., surface milling), using with the milling machine for cutting can be useful to avoid changing and setting different equipments.

The following images help demonstrating these set of conclusions. [Figs. 5.17 and 5.18]

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Milling

Water-Jet Cutting

Laser-Cutting

Milling

Water-Jet Cutting

Figure 5.17 Final pieces with straight (top) and curved (bottom) geometries. The details demonstrate that water‐jet cutting leaves the sharpest vertical surface.

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Figure 5.18 Comparative close up of the cutting surfaces left in the geometrically straight (top) and curved (bottom) parts. In both cases, the laser‐cut piece is above, the milled one is in the center, and the water‐jet cut is bellow. The superior quality of the last one is evident.

E.1.2 Cutting Tolerance

Goal One of the material challenges faced by designers is the tolerance with which a positive and a negative element with the same shape may be cut to allow the former fitting in the later. At this point, material and manufacturing constraints can interfere in the design dimensions required for each elements, to assure an efficient connection for. As a result, although both positive and negative elements virtually share an identical shape, their

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drawings for fabrication may be slightly different. Thus, the goal of the present experiment is to get a sense of the tolerances for cutting pure cork agglomerate shapes towards the exploration of snap‐fit type of connections.

Such design and fabrication interest can be particularly interesting in the case. Unlike the majority of building construction materials, pure cork agglomerate is viscoelastic, which suggests the possibility for connection under pressure, without extra fixture elements.

Test Description The Cutting Tolerance experiment consisted in fabricating and testing snap‐ in connections. From a 2D shape designed in Rhino, a negative and a positive are cut in a pure cork agglomerate board. For evaluating tolerances for such type of connections, five versions of the positive are drawn in rhino with different contour sizes. With 1mm incremental offset variation, two of these versions are smaller than the original one, while the other three are larger. In these experiment two different shapes were tested: one curvilinear and another one straight. [Fig. 5.19]

Figure 5.19 Original CAD drawings, with the indication of the side for cutting, and the dimensional variations.

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Carried out in different places, this experiment tried three different CNC cutting processes: 

laser‐cut (Lasindustria),



water‐jet cut (Vetor3)



milling machine (IAAC)

The material used were standard boards of pure cork agglomerate, with: 

thickness: 30mm (laser + milling), 40mm (water‐jet)



area: 1000x500 mm



density: 120Kg/m3 (standard)

CAD/CAM Process The laser cutting of the pure cork agglomerate board followed the preparation procedures described in the previous test. During the fabrication the difficulty for cutting through the material was again observed. In the end, some of the pieces had to be detached by hand, by breaking some parts that were not perfectly cut. Nonetheless, it was interesting to check the virtually non‐thickness of the laser cuts. [Fig. 5.20]

Figure 5.20 Laser‐cutting process.

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Following the preparation procedures of the previous test, the fabrication experience of water‐jet cutting the pure cork agglomerate board was also similar. Because the cutting lines have a thickness in this process, the cut pieces become separated from the back to its original position. In this case, it could collide with machine at some point and then be damaged. Finally, the straight edge shapes got their corners slightly rounded due to the programming issue described in the previous experiment. [Fig. 5.21]

Figure 5.21 Water‐jet cutting process.

In the milling machine, the same support structure of the previous test was used to fix the pure cork agglomerate board. Then, in the fabrication process, the final moment of cutting each piece continued to be a critical one. When the piece was almost totally free from the surrounded material, its movement produced an interference on its contour cutting. Naturally, this is a problematic situation considering the present experiment’s goal, which could be solved, or minimized, if a vacuum bed was used. Nonetheless, it is not practicable to keep the pieces fixed by hand throughout the whole fabrication process. Finally, due to the cylindrical shape of the milling tool, the problem with the rounded corners of the straight angles continued to exist. To minimize this, the center of the tool was programmed to move along the drawing lines. The expression of the rounded corners was thus smaller and the contour cutting of the negative and the positive shapes could thus coincide. [Fig. 5.22]

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Figure 5.22 Proposed classification of digital technologies in architecture.

Results Confirming the features of each cutting process pointed out in the previous test, the present experiment showed that the best pieces for assuring a strong snap‐in connection were: 

in laser‐cutting, the one with 2mm extra;



in water‐jet cutting, the one with 1mm extra;



in milling, the one identical to the original

Unlike other building construction materials, the viscoelasticity of the pure cork agglomerate allows using in some cases larger size elements to fit in a hole by means of some lateral pressure. Then, when this force is released, the connection becomes strong by itself due to the natural expansion of the material. [Fig. 5.23 and 5.24]

Conceiving larger positive connections for fabrication can thus be an interesting option when using pure cork agglomerate.

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Figure 5.23 Final pieces produced by laser‐cut (top), water‐jet cut (center) and milling (bottom).

In this images it is possible to realize the different cutting thickness in the processes.

Figure 5.24 Laser‐cut part: testing snap‐in connections.

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Water‐jet cut part: testing snap‐in connections.

Milling part: test snap‐in connections.

E.1.3 Design Test – “Clover Panel”

Goal Drawing from the previous experiments on 2D Shape fabrication, the “Clover Panel” design test consisted in the production of a pure cork agglomerate board with an ornamental shape based on geometric pattern. Taking advantage of CNC contour cutting the goal was examining the viability for digitally produce a sophisticated 2D shape. Being hard to be done with conventional manufacturing processes used in the cork industry, this design test aims to check opportunities for expanding the limitations of the industrial production processes.

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Test Description For this experiment, a clover leaf motif served as the base for designing a curvilinear shape that was arranged in a repetitive pattern. Comprising internal cuts, this pattern would not be easy to be done with traditional processes [Fig. 5.25]. A critical aspect on this test resided in the small width of the designed shapes, which could become too fragile.

Figure 5.25 Original CAD drawing.

Carried out in different places, this experiment tried three different CNC cutting processes: 

laser‐cut (Lasindustria),



water‐jet cut (Vetor3)



milling machine (IAAC)

The material used were standard boards of pure cork agglomerate, with: 

thickness: 30mm (laser + milling), 40mm (water‐jet)



area: 1000x500 mm



density: 120Kg/m3 (standard)

CAD/CAM Process In this experiment, the cutting lines crossed out the material boundaries.

Thus, fixing the material on the machine’s bed became a critical procedure to avoid collisions with the adjacent fixture devices. While in laser‐cutting and water‐jet cutting the situation did not require any special care, the salient screws of the support structure on the milling machine called for a special attention. In this case, a CAM simulation helped to check and confirm that

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their location was problematic. Trying to avoid a real collision, the cutting lines located next to the screws were erased for the generation of the CAM instructions, and the pattern was thus partially cut. Although for the purpose of this experiment this was not problematic, the pattern could have been fully fabricated if a different fixation system was previously thought without salient elements.

With the acquisition of a general knowledge about the behavior of pure cork agglomerate in the three fabrication situations, it was not expected any special surprise besides the particular problems noticed before. For instance, the difficulty in achieving a perfect cut through the material with the laser, or the precision interferences caused by the movement of the pieces when their contour cutting is about to finish in the milling machine. Nonetheless, because the drawing pattern was totally curvilinear the problem of the rounded straight corners in the water‐jet cutting and in the milling machine did not occur. In this context, all three fabrication processes served to cut the ornamental panel. [Fig. 5.26, 5.27 and 5.28]

Figure 5.26 Laser‐cutting process.

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Figure 5.27 Water‐jet cutting process.

Figure 5.28 Milling process.

Taking advantage of the milling machine, it was possible to do an extra test with this cutting technology. Reducing the scale of the line pattern, a new pure cork agglomerate board was cut. In this experiment, the material parts were much more thinner and delicate. With the milling tool moving against the material, a couple of the parts broke during the process. However, it was evident that incrementing the density of the material could solve this issue, at this small pattern scale. [Fig. 5.29]

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Figure 5.29 Milling process of an extra panel, with a smaller pattern.

Results Observing the three different cutting technologies, this design test continued confirming the comparative analysis of the first experiment. Regarding the present goal, the intricacy of the geometric pattern demonstrated the ability of digital technologies for cutting any kind of 2D shape in pure cork agglomerate material. Among the different tested processes, the use of water‐jet cutting emerged as the most interesting option for sustaining mass customization and geometric freedom design interests. Indeed, assuring a good quality and precision, this process virtually has no limits in cutting any kind of 2D shape, independently of its complexity. A last consideration should be made regarding the density of the material used in this test. When thinking in innovative visible applications for pure cork agglomerate, a higher density than the standard one is used in this experiment (102Kg/m3) should be explored. Thus, cutting 200Kg/m3 or 300Kg/m3 boards will considerably improve the cutting quality and also the possibility to explore more delicate and refined geometric drawings. [Fig. 5.30, 5.31 and 5.32]

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Figure 5.30

Final panels fabricated by

(center) and milling (right).

laser‐cut (left), water‐jet cut

Figure 5.31

Cutting quality. The water‐jet

generates a better finishing

cut is more precise and than laser‐cutting (left) or milling (right).

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Figure 5.32 Extra milled panel, with a tighter pattern.

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EXPERIMENTS: SURFACE TEXTURE

E.2.1 Step-Over Parameter

Goal In milling processes, the tool‐path definition is a crucial definition from which both fabrication time and finishing quality depend on. It consists on the selection of a geometric trajectory (e.g., parallel) and the value of the step‐over parameter, which represents the separation distance between each adjacent milling trajectory. [Fig. 5.33]

Figure 5.33 Step‐over illustration from VisualCAM software.

The negotiation of the production budget and design intentions is a determinant factor in the decision of the tool paths, and it can vary between different disciplines. For instance, in mechanical engineering, the milling of parts usually aims to achieve an extreme level of precision and a high‐quality surface finishing. Implying long machining time, the tool‐paths are defined very tight to avoid generating surface textures. On the contrary, dealing with different goals and precision requirements, architects may find interesting the exploration of textures created by the milling tool on the material’s surface. Adding to this design intention, such decision implies also a less machining time that brings cost benefits.

Thus, the goal of the present experiment is twofold: 

examining how the step‐over parameter of a tool‐path can affect the balance between fabrication time and surface finishing quality, from smooth to rough;

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investigating the material capacity to represent texture. Due to the granulate nature of pure cork agglomerate, and the low‐density of the testing material used, it was not sure if it could define a texture without disintegrating with the movement of the tool.

Test Description For the “Step‐Over” experiment, a double curved surface was designed in Rhino, reaching a 40mm depth on its lower points. This form was then repeated five times so that each one could be then milled according to different step‐over settings assigned to a single milling tool. From such common geometric condition and milling tool, different texture effects could thus be read and compared. [Fig. 5.34]

Figure 5.34 Original CAD model and milling tool paths for each section.

surface 1 surface 2 surface 3 surface 4 surface 5

For this experiment, two milling tools were employed. According to the image above, surfaces 1, 2 and 3 were milled with a 12mm diameter tool, while surfaces 4 and 5 used another one with a 4mm diameter. Both had a nose ball shape.

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The present experiment was conducted with a 3‐axis milling machine (IAAC), and the material used was a standard board of pure cork agglomerate with: 

Thickness: 60 mm



Area: 1000 x 500 mm



Density: 120 Kg/m3 (standard)

CAD/CAM Process With the cutting drawing crossing out the material boundaries, fixing the material on the machine’s beds became a critical procedure. In this case, some lateral fixture devices supported the board without creating interferences above the board’s height level. The milling tool could thus run freely over the stock.

With the goal just focused on the finishing quality, a single roughing cut program was applied to all surfaces in a single operation, leaving 4mm of material to be removed with the final finishing cut operation. Departing from the same material condition, 5 different milling programs were run following parallel straight trajectories, each one with a different step‐over value. [Fig. 5.35]

Figure 5.35 Proposed classification of digital technologies in architecture.

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The following table [Fig. 5.36] resumes the fabrication parameters that were chosen and the time each finishing cut operation took.

Figure 5.36

Tool

Surface

Machining

diameter

number

Step over

Finishing milling time

12 mm

1

12 mm

2m 30s

2

7 mm

3m 30s

3

3 mm

8m 40s

4

12 mm

2m 30s

5

3 mm

8m 40s

4 mm

Fabrication parameters.

Results The development of this experiment raised several conclusions. The first one, was the observation that although sharing common geometric, material and fabrication conditions, different step‐over parameters have produced quite different texture effects. This fact can be easily seen in the following image.

[Fig. 5.37]

surface 1

surface 2

surface 3

surface 4

surface 5

Figure 5.37 Comparing the texture effects of the final milled parts.

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A second conclusion confirmed the potential of pure cork agglomerate to reveal texture, despite its granulate nature. The exploration of surface texture with this material seems thus to be a viable option that can be interesting for architects and designers. [Fig. 5.38]

Figure 5.38 Final milled board showing some shadow effects.

Finally, it was possible to verify that the time consuming difference between the roughest and the smoothest surfaces cannot be ignored when exploring this material possibility in architecture. Indeed, the fact that milling surfaces 3 and 5 took almost four times more than milling surfaces 1 and 4, means that the price of such a design intention will also cost about 4 times more. If one considers the discussion around the scale of architecture, and the amount of material production that it may involve, such a design intention could quickly become unfeasible. In many situations, the consideration of material textures in architecture become an interesting solution for taking advantage of both ornamental effects and fast production time.

E.2.2 Step-Down Parameter

Goal Continuing to investigate the material effects produced by decisions on surface milling parameters, the step‐down is another important feature to take into account. By defining the material’s depth removed by the tool in each milling passage, it affects the production quality and speed. For

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instance, although choosing a deep step‐down can shorten the production time (i.e., the machine has to run fewer times on the stock to remove the desired amount of material), it can also create some fabrication problems deriving from the material’s and tool’s resistance. If the material is hard, the machine must run with low step‐down values to compensate its own limitations of power and resistance. Breaking the tool in such conditions is an accident that can easily happen. On the contrary, if the material is soft, the machine can explore deeper step‐over values.

In this context, the present experiment examined milling a pure cork agglomerate board by testing different values of step‐down with the goal of understanding opportunities for optimizing such production processes.

Test Description This very simple experiment consisted in milling three rectangular areas of a pure cork agglomerate board, testing the following step‐down parameters: 

4mm



12 mm



24 mm

To perceive the eventual interference of the tool size, this experiment was repeated with tools with 14 mm, 25 mm and 54 mm diameters, each one on an individual pure cork agglomerate board. [Fig. 5.39]

Figure 5.39 Original CAD model.

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The present experiment was conducted with a 3‐axis milling machine (IAAC), and the material used was a standard board of pure cork agglomerate with: 

Thickness: 30 mm



Area: 1000 x 500 mm



Density: 120 Kg/m3 (standard)

CAD/CAM Process Conveniently locating the surfaces in the middle of the panel, it was possible to fix the board with the wooden support used in previous experiments. For perceiving the resulting differences, all surfaces were milled following the same parallel trajectory. For each tool, the step‐down was determined as 50% of the its diameter, as a common criteria.

In each milling test, the observation of the material reaction allowed to drive the three subtractive operations with the same spindle speed and cutting speed settings. Because the cutting depth parameter was the only one that changed, there was no difference in terms of fabrication time between the three surface milling. [Fig. 5.40]

Figure 5.40 Milling process.

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Results The milling of these surfaces released thin cork particles, with their size tending to augment with the increasing of both the step‐down parameter and the size of the milling tool. In the case of the largest tool, the granules jumped out at high speed with some of them having big proportions. Curiously, on each board, this fact did not seem to affect the quality of the surface finishing, as it can be seen in the images bellow. [Fig. 5.41 and 5.42]

Figure 5.41 Final boards milled with the different tools.

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Figure 5.42 Different granulations released when milling the board with different cutting depths.

In this context, the material consistency of pure cork agglomerate products seem to encourage the programming of deep step‐down parameters, independently of the tool size. The immediate benefit of such option is the possibility to fabricate surfaces in a few milling levels. In a certain way, from this experiment, the step‐down limitations seemed to be more tied to the length of the available tool rather than to the pure cork agglomerate constraints. In other words, a thicker material seems to easily support being cut by longer tools in single passages, which spares a lot of fabrication time.

At the same time, the cork granules released during this subtractive process have an appropriate size for recycling purposes, which is also a highly positive factor.

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E.2.3 Speed Parameters

Goal Depending on the machine rigidity and material resistance properties, the spindle speed and the cutting speed are two key parameters that must be negotiated for optimizing a milling process. While the first one describes the tool’s rotational frequency (rpm – rotations per minute), the second one describes the speed difference between the cutting tool and the material’s surface (m/min. ‐ meters per minute). Surface finishing quality and fabrication speed still depend thus on the calibration of these factors.

Investigating the impact of such parameters when milling a pure cork agglomerate board is thus the main goal of the present experiment.

Test Description To test different conditions, a double curved surface generated in Rhinoceros was repeated nine times over a pure cork agglomerate board. Considering three different spindle speeds and three different cutting speeds, these surfaces were arranged in a 3x3 matrix configuration. Each of these areas were thus milled following a specific combination of spindle and cutting speeds. For this experiment, it was decided to use the largest milling tool.

The resulting fabricated board aimed to reveal the spectrum of the material effects caused by the such fabrication decisions. [Fig. 5.43 and 5.44]

Figure 5.43 Original CAD model.

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cutting 30 spindle 5 000

cutting 60 spindle 5 000

cutting 75 spindle 5 000

cutting 30 spindle 10 000

cutting 60 spindle 10 000

cutting 75 spindle 10 000

cutting 30 spindle 15 000

cutting 60 spindle 15 000

cutting 75 spindle 15 000

Figure 5.44 Speed parameters for milling

each board section.

The experiment was carried out with the 3‐axis CNC milling machine at IAAC. Using a board of pure cork agglomerate with: 

Thickness: 60 mm



Area: 1000 x 500 mm



Density: 120 Kg/m3 (standard)

CAD/CAM Process Using the wooden support structure employed in previous experiments, the surfaces were milled without any initial roughing cut, without revealing any surprise [Fig. 5.45]. The only fact deserving to be acknowledged was the observation that larger cork particles were released at greater spindle and cutting speeds. The velocity with which they jump out the material was also faster in those circumstances.

Figure 5.45 Milling process.

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The following table resumes the speed settings that were used and the fabrication time resulting from such decisions. [Fig. 5.46]

Figure 5.46

Cutting Speed

Proposed classification of digital technologies in

Spindle Speed

30

60

75

5 000

1m 49s

1m 11s

0m 56s

10 000

1m 52s

1m 10s

0m 57s

15 000

1m 53s

1m 13s

0m 59s

architecture.

Results An overall look into the machined board reveals no significant difference of finishing quality between all milled surfaces. The material’s heterogeneous composition and color played here an important role in camouflaging any difference evidence. [Fig. 5.47]

Figure 5.47 Final milled board.

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However, a closer look into the board allows to perceive that the influence of the cutting speed can be more decisive than the spindle speed. For instance, when looking into all surfaces that were milled at 5.000 rpm spindle speed, there was a visible loss of texture definition when the cutting speed was increased. Between the 30m/s and the 75m/s, such difference is clear. In this higher cutting speed, the increasing of the spindle speed from 5.000 to 15.000 rpm worked to produce, again, a better finishing texture. [Fig. 5.48]

In this context, the comparison of the two most extreme scenarios suggests

Figure 5.48

that there is no advantage in running the tool at lower speeds when working

Comparison between

with the pure cork agglomerate board. Without no major design implication, this fact encourages exploring machining this material at high speeds to get important cost benefits, as it can be easily deduced from the time consuming differences expressed in the table above.

E.2.4 Tool Geometry

Goal Especially for those interested in exploring surface textures, the geometry of the milling tool determines the final machined effect. Unlike a cylindrical tool, a spherical one produces different textures depending on its cutting depth.

For this reason, architects and designers can take advantage of choosing the

different finishing qualities.

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right tools in order to create material effects that are not drawn in CAD files.

Demonstrating an economy of means and a certain process intelligence, design intention can thus be extended into the moment of fabrication, collapsing two moments that traditionally understood as separate.

Thus, the goal of the present experiment is to examine the possibility for generating different surface effects in pure cork agglomerate materials, through the selection of machining tools, instead of drawing them in CAD models. The articulation of such digital fabrication sensibility with the capabilities of digital modeling is a crucial condition for driving clever and efficient production strategies in architecture.

Test Description For this experiment, the CAD information was reduced to a minimum in order to highlight the contribution of the milling tool for the resulting machining effects [Fig. 5.49]. Departing from a simple straight line in plan, the following five different variations were defined: 

Planar curve with 3mm depth



Planar curve with 9mm depth



Planar curve with 24mm



Spline curve



Polyline curve

TOOL DIAMETERS:

54mm / 24mm / 12mm

Figure 5.49 Original CAD drawing and model.

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The five different lines served thus as trajectories for testing three tools with different geometries [Fig. 5.50]: 

Spherical tool with 54 mm diameter



Spherical tool with 25mm diameter;



Cylindrical tool with flat end, with 12mm diameter;

Figure 5.50 Milling tools used.

The experiment was carried out with the 3‐axis CNC milling machine at IAAC, and the material used was a board of pure cork agglomerate with: 

Thickness: 60 mm



Area: 1000 x 500 mm



Density: 120 Kg/m3 (standard)

CAD/CAM Process Before machining, the use of Visual Mill, the CAM software, allowed to preview the final machining effects created by the different tools out of simple CAD lines. Then, the CNC milling occurred as in the previous experiments, without any relevant or unexpected occurrence. The process was fast, with the exception of the need to change tools and reset the Z level of the machine on each time. Learning from the previous experiment, it was decided to follow average speed values, with cutting speed set to 50 m/min. and the spindle speed to 10000 rpm. [Fig. 5.51]

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Figure 5.51 Milling process.

Results The development of this experiment served to confirm the powerful role played by the tool geometry in producing material effects. On one hand, as expected, the use of a cylindrical tool produced an easily predicable result due to its constant diameter along its height. On the other hand, the spherical tools, when cutting at different material depths, produced various material effects, which were not designed nor predicted in the CAD files. It was by foreseeing this potential, that the largest tool was specially designed and manufactured for this dissertation. When looking to the part of the board milled by this tool, it is interesting to verify and reflect on how such a simple and virtually no thickness computer line can originate such visible and expressive 3D surface effects. [Fig. 5.52]

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54mm

24mm

12mm

The power of such CAD/CAM combination is thus invaluable. To perceive the minimum information that must be digitally designed by realizing the maximum effect that can be performed by machine tools, is an important challenge for those interested in exploring these processes in architecture.

This negotiation is a skill that can make feasible the materialization of certain design intentions, which, otherwise, would not be possible due to the redundancy of separated CAD and CAM works.

The ability to draw with the machining tool thus result from a close contact of the designer with the fabrication processes. In this case, CAM software is not used just as a software for automatically generating machining instructions from CAD drawings and models, but actually, instead, as a software environment where design thinking and visualization can occur by exploring the use of different drawing tools – the machine tools.

Figure 5.52 Final milled lines.

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E.2.5 Design Test – “Waving Panel”

Goal The present design experiment aimed to produce a pure cork agglomerate board with an ornamental surface texture, applying the experience acquired in the previous tests. Facing the flatness that characterize the existing cork products in the market, the goal is to investigate the potential of CAD/CAM technologies to open the door for surface texture customization.

Test Description Exploring the potential of means economy of integrated CAD/CAM processes, a textured panel was conceived based on a series of repetitive undulated straight lines [Fig. 5.53]. By using the 54mm diameter tool, this panel intended to demonstrate how an expressive and consistent texture can be quickly produced.

Figure 5.53 Original CAD drawing and model.

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After the production of a first panel, it was decided to fabricate a second one milled in both sides, and with the introduction of a set of variable perforations [Fig. 5.54]. The versatility of the milling machine allowed running two different fabrication processes: milling and cutting. In this last operation, it was used a cylindrical and flat end tool with 14mm diameter.

Figure 5.54 CAD drawing with the incorporation of holes.

The present experiment was conducted with a 3‐axis milling machine (IAAC), and the material used was a board of pure cork agglomerate with: 

Thickness: 60 mm



Area: 1000 x 500 mm



Density: 200‐300 Kg/m3 (high density)

CAD/CAM Process The wooden support with the screws was used again for fixing the pure cork agglomerate board for this experiment. However, because its whole surface had to be entirely milled, the screws could not emerge on the top of the material, otherwise, they would collide with the machine. To avoid this, the solution was placing an extra board on the bottom to lift up the level of the working panel sufficiently to keep the screws bellow the milling level.

Defined in the CAD drawing, the milling process consisted only in fourteen straight and parallel passages of the tool, with no roughing cut. By setting up the cutting speed to 40m/min and the spindle speed to 4000, the whole surface was milled in just 7m.30s.. A quick extrapolation points towards the

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possibility for milling about 8 panels/hour, which correspond to 4 sq/m of material. [Fig. 5.55]

Figure 5.55 Milling process for making the waiving texture.

The production of the second panel followed the same procedures. However, for milling its backside, the board had to be flipped down, and was fixed by using the same hidden screws. Because the milled surface geometry was regular, there were no problems to keep the board leveled during that fabrication process. In the end, for cutting the perforations, a tool change was required. Producing the 42 holes took about 9m.40s., with most of the time being consumed with the tool moving in the air, displacing from hole to hole.

[Fig. 5.56]

Figure 5.56 Milling process for making the perforations.

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Results The development of this design test confirmed the possibility for using a subtractive fabrication process with pure cork agglomerate material for the production of surface texture effects. A close look on the fabricated panels reveals a precise and smooth finishing quality. However, the cutting of the perforations was not so good, though it was very acceptable. Recovering the 2D Shape experiments, the fabrication of the perforations could have been done better with a water‐jet cutting. In this scenarios, changing machines or accepting a lower finishing quality are decisions that must be evaluated by the architect when facing such scenarios.

Considering the technical and material conditions described above, the use of CAD/CAM processes and CNC milling with pure cork agglomerate material really open the door for exploring custom surface design strategies towards the production and commercialization of new products, like, for instance, decorative panels for wall finishing, stand‐alone screens, etc. [Fig. 5.57, 5.58 and 5.59]

Figure 5.57 Final panel with the waving texture.

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Figure 5.58 Detail of the waiving texture.

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Figure 5.59 Final panel with the waiving texture and the perforations.

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EXPERIMENTS: 3D FORM

E.3.1 Design Test I - “CorkStruct”

Goal Recent innovative applications of pure cork agglomerate in architecture have consisted in exploring the use of blocks as an exterior facade material.

However, the formal limitations of the existing commercial products have narrowed their application as a cover for flat and orthogonal building surfaces, based on standard components arranged in repetitive tiling. This is the case of the Portuguese Pavilion designed by Álvaro Siza where the absolute flatness of the vertical walls contrast with the free form curvature of its roof, From the perspective of this dissertation, this testifies the vast design opportunities opened by new materials and the limited ones offered by the traditional ones.

In this context, the present design test is called CorkStruct, and consists on a first experiment to investigate the possibility for materializing three‐ dimensional free form blocks in pure cork agglomerate. Its ultimate goal is the production of a first physical prototype towards the conception and construction of free‐form architectural walls and structures with this material.

Test Description The diverse knowledge acquired with the previous experiments on 2D Shape and Surface Texture led to approach the present research on 3D Form through the direct realization of a design experiment.

Going beyond current standard formats, three building blocks with a continuous curvature were designed in Rhinoceros. To try different formal situations, the curvature geometry in one face is very smooth while it is more aggressive and bumpy in the opposite one. [Fig. 5.60]

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For connecting the three blocks, it was devised a system of standard

Figure 5.60

perforations placed in their bottom and top sides, which play a double role:

Proposed classification of



assuring different relative connection possibilities between the blocks, drawing a simple logic of structural assembly;



offering points of anchorage to position and support the block during the machining processes on both sides.

The standard nature of the perforations became important because: 

it helped the fabrication process allowing the use of a common supporting system for all the blocks;



one could think of easily implementing it in a mass production. industrial set‐up.

Exploring the combination of standard an non‐standard logics was at the core of this design test. This kind of negotiation is frequently an essential condition for the efficient implementation in practice of CAD/CAM processes.

Fabricated in wood, the supporting structure permitted sustaining the block during the machining process by means of sticks. Assuring their right positioning and leveling, this structure allowed milling in both sides without having to reset the machine position or changing the supporting structure.

The following image describes the complete process for machining a block in both sides. [Fig 5.61]

digital technologies in architecture.

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Carried out with the 3‐axis CNC milling machine at IST, the raw material used

Figure 5.61

in this test were standard pure cork agglomerate blocks with:

Producing the supporting



Thickness: 200 mm



Area: 600 x 300 mm



Density: 200 – 300 Kg/m3 (high‐density)

CAD/CAM Process Once fixed the wooden structure in the machine bed, it served as the supporting system for milling all the three pure cork agglomerate blocks. The Z level of the machine was set‐up in the first block and, afterwards, there was not the necessity to reset it again. Thus, the whole machining process unfolded very smoothly, just requiring to flip and switch the blocks, and running each individual milling program. [Fig. 5.62]

wooden structure (top) and sequence plan for milling the block in both sides (bottom).

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Considering the work piece positioning in the supporting system, the generation of the CAM instructions defined a roughing cut and a finishing cut.

Figure 5.62 Milling process.

Using a cylindrical tool with 12mm diameter, the first operation took about 10‐15 minutes to be accomplished while the second one took about 30‐40 minutes to be completed. [Fig. 5.63 and 5.64]

Figure 5.63 Close‐up of the milling tool over the material, when doing the finishing cut.

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Results

Figure 5.64

Observing the machining process and evaluating the final prototype [Fig.

The final milled surface in

5.65 and 5.66], it was possible to highlight the following positive

of two blocks.

both sides, and the assembly

considerations: 

The supporting structure, though very simple, worked efficiently for supporting and orienting all the blocks for each machining operation;



In both sides, the machined surface presented a good definition;



Once assembled, the geometric continuity between the fabricated blocks is quite precise. The existing differences are within a maximum tolerance of 5 mm.



During the process, the removed material was released in the form of tiny granules which facilitated its collection in the end and consequent recycling possibilities.

Figure 5.65 Final assembled structure.

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Figure 5.66 Close‐up of the final assembled structure.

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Regarding the fabrication time, it seems to have been quite excessive for a regular practice. However, it can be explained by two reasons: 

the small size of the tool used, which naturally requires longer tool paths more time to mill the whole surface.



the extremely tight tool paths that were defined for the finishing milling. As a result, the surface finishing was very smooth, and the visibility of the passage of the milling tool was very subtle.

Thinking in overcoming this situation, it is not difficult to be confident that with a bigger tool and accepting more surface texture in the final blocks, the fabrication time could be substantially reduced for less than a half of the time.

As an overall appreciation of the final assembled prototype, its aesthetic and formal results were very interesting. It is curious to observe how the natural texture of the material also contributed for the image of continuity of the structure. The possibility to express three‐dimensional curvature and variation in pure cork agglomerate applications in architecture was demonstrated to be a real possibility.

E.3.2 Design Test II - “FreeForm Panel”

Goal The second design test, in the scope of the 3D Form research, tried to push forward the free form possibilities for pure cork agglomerate building components. The goal was the production of a double side curved panel with a more accentuated curved shape, that could serve as a prototype for imagining any freeform shape materialized in this material.

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Test Description This test started with the design of a double curved surface in Rhino that could sustain multiple associative combinations without losing geometric continuity. With a variation of 12cm in height, this surface is inscribed in the volume of the pure cork agglomerate block. To mill it in both sides, two machining phases had to be carried out involving flipping the material between them. The thickness of this piece was designed to have 5cm. [Fig. 5.67]

Figure 5.67 Original CAD models and assembly studies.

Carried out with the 3‐axis CNC milling machine at IAAC, the raw material used in this design test were standard pure cork agglomerate blocks with: 

Thickness: 200 mm



Area: 600 x 300 mm



Density: 200‐300 Kg/m3 (high‐density)

CAD/CAM Process Considering the degree of curvature of the surface, the largest milling tool could cause some problems when machining the most steeped parts. For this reason, it was decided to use the spherical tool with 25mm diameter for this design test.

To achieve the desired curved surface, it was necessary to remove a large amount of material in the beginning. Thus, each face was produced with a roughing and a finishing cut operations. [Fig. 5.68]

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For milling the first side, the pure cork agglomerate block was directly fixed on the table with the help of mechanical fixtures laterally located. The machine could thus run freely on the material. While the rough cutting took

Figure 5.68 Milling simulation. From the roughing cut (top) to the finishing cut (bottom).

about 45 minutes, because there was a lot of material to be removed, the finish cutting was completed in just solely 15 minutes. [Fig. 5.69]

For milling the second side, it was necessary to find a way to support the

Figure 5.69

piece. Given that all blocks shared the same surface geometry, it came the

Milling process.

idea to mill a Styrofoam block with that same surface and use it as the support. Thus, by flipping the cork piece, it perfectly matched the Styrofoam one, which provided a stable support for the new machining operation. The materials geometry also contributed to avoid slippery, which dispensed any extra fixture element. [Fig. 5.70]

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Figure 5.70 Milling the Styrofoam support (top) and the second side of the cork panel.(bottom).

In the end, the pure cork agglomerate piece was removed from the support in perfect conditions. The use of the Styrofoam piece was a very easy and efficient way to facilitate the control of the double side milling process.

With this test, two blocks were milled on just one side, while another one was milled in both sides. In this 3D curved panel, it was decided to leave one of its sides showing just the effect of the rough cutting. In this case, besides resulting machining time, the aesthetic and material qualities emerging from the roughing cut appeared indeed very interesting from the design point of view.

Results The present design test could be considered as a successful one. The machining process was simple and did not present any problem, and the material effect resulted interesting. [Fig. 5.71, 5.72 and 5.73]

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Figure 5.70 Final milled panel, showing the textured side.

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Figure 5.71 Final milled panel, showing the smoother side.

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Figure 5.72 Side view of the final milled panel, showing its 3D curvature.

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The accuracy of the CNC milling process and the capacity of pure cork agglomerate board to define surface texture were confirmed with this experiment. The perfect assembly of all pieces in several configurations testified such a high level of fabrication control. [Fig. 5.74]

With this design test, it became clear the positive contribution of CAD/CAM processes to make technically feasible the production of complex forms in pure cork agglomerate boards. Unlike many other materials, the fact that all wasted material can find a recyclable destiny, makes more sustainable the exploration of subtractive fabrication processes with cork.

Knowing that it depends on the surface geometry to be milled, the CNC milling processes are usually expensive ones. With the pure cork agglomerate, despite some possibilities to optimize the machining time, it should be acknowledged that it can yet be considered relatively high. This fact tends to assume that the exploration of 3D forms with pure cork agglomerate can be an expensive process, even despite the recycling possibilities.

Figure 5.74 Assembly configurations using the same three milled panels.

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EXPERIMENTS: OTHER

E.4.1 Design Test - “Cork Stoppers Panel”

Goal After the previous experiments on material design themes, it was decided to do an extra design test with pure cork agglomerate board, inspired by the observation of the importance of cork stoppers in the cork industry. Called Cork Stoppers Panel, the present test aimed to fabricate perforated panels in pure cork agglomerate for snapping‐in conventional cork stoppers exploring cork’s viscoelasticity. By controlling the depth variation of such perforations, the emergence of the cork stoppers on the panel can be tooled for creating customized textures, patterns or drawings.

Thus, the Cork Toppers Panel consists on a design solution for translating, or converting, any image or picture into a grid of cork stoppers, resembling a process of pixelation. Through the combination of several panels, large surfaces could be covered to convey interesting material effects [Fig. 5.75].

Figure 5.75 Original CAD studies.

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Test Description The test consisted in developing and testing a complete technique for controlling the generation of customized material effects from the selection of any black and white picture. [Fig. 5.76]

For this test, the starting point was the development, with Photoshop, of a

Figure 5.76

graphic image that could generate, in Rhinoceros, a very similar 3D surface to

From a grayscale image to the

that used in the E.3.2 experiment, because of its interesting versatile

variable perforations.

generation of a 3D surface and

associative combinations. Then, following a regular grid arrangement, the digital curved surface generated with Rhinoceros served as the ground for positioning a set of cylinders simulating cork stoppers, which created a resulting undulated surface. The subtraction of these cylinders to the pure cork agglomerate volume, created a box with variable perforations. [Fig. 5.77]

Taking advantage of the viscoelasticty property of pure cork agglomerate, the

Figure 5.77

holes were perforated with a 4 mm smaller diameter than that of cork

Original CAD model.

stoppers. By doing so, it provided a tight snapping‐in connections that did not require any extra gluing or fixing system,

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Finally, this design test comprised the manufacturing of two identical panels, in order to test continuity situations resulting from the assemblage of such decorative elements.

Exceptionally, this experiment was digitally manufactured in a different place, at FEYODESIGN company in Oporto (Portugal). Done with their 3‐axis milling machine, it used: 

Thickness: 100 mm



Area: 600 x 300 mm



Density: 200‐300 Kg/m3 (high‐density)

CAD/CAM Process In this design test, the file was sent to the shop, and the perforated blocks were picked up in the end. Although this process was not followed directly, there were no reasons to expect any surprise. The 3D digital model of the perforated box was the info sent o FEYODESIGN for generating the CAM instructions for milling the holes.

After the fabrication, the assembly of the cork stoppers in the panels was done by hand. Fitting tight, every cork stopper was pressed until the end of the hole, which created a resulting undulating effect. [Fig. 5.78]

Figure 5.78

Assembly process: fitting the

cork stoppers in the panel.

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Results This design test combined standard and non‐standard principles in the generation of customized decorative panels, to take the best out of each approach. On the one hand, the design of variable holes, which is a digital process that can be easily automated, provides the base for infinite possibilities for design customization. On the other hand, the use of a regular grid and standard size pure cork agglomerate blocks and cork‐stoppers establishes a condition that can facilitate an eventual automation of the snapping‐in physical process. As a result, the difference –the variable height‐ is perceived out of a regular condition –the grid. [Fig. 5.79 and 5.80]

Figure 5.79 Cork‐Stopper panel and possible group configurations, demonstrating surface continuity.

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Figure 5.80 Cork‐stopper panels.

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CONCLUSIONS

Focused on practical experiments, the present chapter evaluated the possibility of expanding the geometric possibilities of current pure cork agglomerate products through the exploration of CAD/CAM processes.

Considering the three research categories ‐ 2D Shape, Surface Texture and 3D Form – the results demonstrated real possibilities for addressing mass‐ customization and freeform design interests through the exploration of digital manufacturing processes. However, the conditions for making feasible the exploration of such possibilities are not the same in all research categories:



In the 2D Shape research, cutting complex geometries or regular ones require exactly the same effort for the machining processes.

This means that there is no cost variation if one wants to produce a set of rectangular and repetitive contours or a set of curved and customized ones. In other words, using this process, mass customization practices can cost the same as standardized ones. The critical aspect is related with the nesting of irregular pieces on the work piece, which must be carefully planned to spare material and the budget controlled.



On the contrary, in the 3D Form research, the milling of different forms imply specific and different machining times and, consequently, distinct costs. At the same time, the geometric nature of the piece has also a direct influence in those factors. For instance, a curved and deep surface is much more expensive to be fabricated than a flat and superficial one. In the E.3.1 experiment, the milling of the back and front faces took radically different times due to their distinct geometries. Thus, although technically possible, the long time required by these subtractive fabrication processes makes it harder to feasibly respond to design practices dealing with complex shapes and mass customization. In this situation, mass customization is still more expensive than standardization.

However, despite its expensiveness, CNC milling can be the only solution capable for materializing some 3D formal elements. In that same E.3.1 experiment, the production of the undulating and bumpy surfaces would be very difficult to be done with the same precision

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and time using non‐digital means. Thus, this important contribution of subtractive fabrication technologies cannot be thus ignored.



Regarding the viability of exploring Surface Texture manufacturing strategies lies in the middle of the previous two. A careful negotiation between design data and fabrication information is determinant for the economy and feasibility of such surface design explorations. The E.2.5 experiment clearly illustrates how the right decision of fabrication parameters can accelerate that process while it simplifies design procedures and specifications.

The practical investigation of such design opportunities, also served to realize the adequacy of the different CNC fabrication technologies to work with pure cork agglomerate. Described in detail for each experiment, this analysis allowed to conclude that:



Facing 2D fabrication, the use of CNC water‐jet cut technologies revealed to be a very good option, combining speed, precision, cutting power and finishing qualities. Despite its slightly inferior quality, the use of milling machines for cutting can be an interesting option in those cases where other fabrication operations (e.g., milling) are also required. In such cases, the use of a single –milling‐ machine to perform several fabrication operations can bring important cost benefits.



Facing 3D fabrication, the use of CNC milling technologies is indispensible. With some geometric limitations defined by the number of working axis of the equipment, complex forms can be indeed produced with accuracy in pure cork agglomerate. The fact that this material can be recycled is invaluable, because it makes the use of subtractive fabrication a more sustainable process, especially if one compares it with other materials.

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Chapter 6

Conclusion

As explained in the introductory chapter, the objective of this thesis was to investigate whether CAD/CAM technologies could lead to the development of innovative applications of cork in architecture. Behind this departing point, there were two initial arguments: 

That digital technologies have been opening new design and material opportunities that could be perceived in contemporary architectural practice and built works;



That cork products oriented to the building construction industry were still rooted in mechanical industrial processes that limited their capacity for becoming a more interesting material for architecture, despite its evident natural properties.

Research was carried out to confirm and bridge both arguments, as described in chapters 2 through 5, each examining a particular research topic. The present chapter is aimed, instead at: 

summarizing the chain of arguments that were built and evolved in such chapters to test the thesis’ main argument;



discussing the impact of the investigation on architecture and industry;



identifying future research opportunities for continuing and extending the present work.

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6.1 THE DIGITAL CONDITION FOR MATERIAL INNOVATION

Starting by understanding and evaluating the role of digital technologies in architecture, the research described in Chapter 2 demonstrated an undeniable reality; that today the use of digital technologies can interfere in the architectural practice, from conception to construction. With the exploration of CAD, CAE and CAM tools, the use of computers in architecture is no longer limited to virtual representation and simulation but has been extended towards the domain of material fabrication and construction.

The review of relevant digital design and manufacturing technologies for architecture conducted in Chapter 3, helped to clarify the digital condition for the development of architectural projects and its impact in contemporary architectural practice. The integrative exploration of the computer’s representational and calculation capabilities with the flexible and precise production processes sustained by digitally driven fabrication and construction is at the basis of the radical expansion of the world of conceptual and constructive opportunities in architecture.

A quick look into recent contemporary architecture can be revealing. Defying the design and material limits imposed by the standardization paradigm of the 20th Century, architects are increasingly interested in exploring geometric freedom and customization. Buildings with singular forms and unique constructive and material solutions are becoming commonplace.

What is significant here, is that this phenomenon occurs at a global scale and is exercised by from individual architects and small design practices to large architectural firms. Furthermore, it is expressed at many levels (e.g., formal, structural, building component) and diverse building scales (e.g., from small to large constructions).

Within other sectors, the understanding of this scenario is particularly relevant today for the building materials industry. When architects have digital technologies to link their design intentions to the physical realm, materials can have an important role in design foundation and development.

Traditional material selection processes in architecture tend to give place to material design, posing new challenges for the industry, which has to rethink

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its processes, products and services for fitting into this dynamic context.

With the help of digital design and manufacturing processes, one assists today to: 

the emergence of an increasing range of new material products while, at the same time, traditional ones like concrete, wood, glass or metals are experiencing innovative developments and applications;



the offering of material customization services supported by the increasing

integrated

collaboration

between

advanced

manufacturing facilities and research and development units.

In this context, it is hard to determine whether technology is the driving force shaping those interests and desires, or they are motivated by other factors like economic or cultural ones. Nonetheless, this scenario suggests that for the building material industry to become successful, it must overcome traditional production paradigms and play a double role, supported by the contribution of digital design and manufacturing technologies. On one hand, it must be capable of responding to architect’s intentions, providing flexible and adaptive production practices. On the other hand, its role should go beyond this passive position to rethinking its own products and services for triggering architect’s desires and imagination.

6.2 RETHINKING CORK IN ARCHITECTURE

After perceiving the technical and cultural conditions that exist today for material innovation in contemporary architecture, the goal became to choose one material for investigating new application possibilities in architecture.

The chosen material was cork, and more specifically, pure cork agglomerate.

Supporting this option, there was a set of diverse reasons and motivations that were identified and analyzed in detail in Chapter 4. Among these was the contradiction between its enormous potential and its limited use. In fact,

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although pure cork agglomerate is a 100% natural and recyclable material with a remarkable combination of properties, which are invaluable qualities facing today’s world ecological threats, its potential for building construction has been narrowly exploited due to several of factors.

Among them, two deserve a particular reference: 

being a secondary commercial area within the cork industry, the sector of pure cork agglomerate production is still rooted in mechanical paradigms based on standardization, which offer very few design possibilities;



the traditional understanding of pure cork agglomerate as an insulation material has narrowed its application to hidden and interior applications, thereby reducing its attractiveness for architects.

Within a field with few innovation initiatives, the exploration of pure cork agglomerate as an external building material by Álvaro Siza in 2000 opened up a new field of application for this material. The possibility of defining the exterior form of a building with a natural material like cork is crucial for seducing architects, as the facade has been traditionally the part of the building where architects put their best effort. Extending its business to this territory is thus a great commercial opportunity for the cork industry nowadays, especially in a moment where its core business – the cork stoppers production – is facing important threats. Since then, architects have rediscovered this material, as the increasing number of exterior facade applications in the last years clearly indicates.

Nonetheless, the entrance in the market of building materials and solutions for architectural facades is not by itself a sufficient condition for the success of the cork industry. Facing the severe competition of other materials ‐new and traditional ones‐ pure cork agglomerate has interesting arguments to show but also some evident limitations. With the investigation conducted in Chapter 4, it became evident that among the later, its standard and regular design options available in the market tend to prevent it from matching contemporary architectural design interests. For instance, facing the construction of irregular or curved geometries, many other building material

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industries (e.g., wood, stone, concrete, metals) have been capable of offering products and solutions for addressing such challenges.

Thus, the set of practical experiments presented in Chapter 5 investigated the possibility of CAD/CAM technologies opening up new design opportunities for using pure cork agglomerate in architecture. Research concentrated on adding a digital manufacturing stage to the end of the current industrial production chain and its results, demonstrated the technical viability of such hypothesis. By overcoming the production of standard rectangular shapes with flat surfaces, CAD/CAM fabricated pure cork agglomerate products can indeed exhibit variable contours, customized textures, and irregular forms.

From the economic point of view, the introduction of an additional manufacturing step can imply an increase in the final production. However, this might not be a problem, as the resulting material design achievements, spotting innovation and customization, can represent an added value. Unlike other synthetic products, which can be produced endlessly, it should be remembered that pure cork agglomerate is a natural material whose main commercial target is a range of applications where an added value is appreciated and desired. The growing focus of contemporary architecture on design uniqueness and sustainability concerns has drawn favorable conditions for a renewed interest in pure cork agglomerate products. By unveiling such new material design possibilities, its value as an exclusive and unique building construction product can definitely be reinforced and appreciated.

However, such potential can only be fulfilled when the subjacent technologies are implemented in practice, and the industry and designers accepts and integrates them in their work. The resulting benefits for the industry can then be foreseen in two business areas: 

the expansion and offer of new customized design products, conceived and produced with CAD/CAM processes;



the offer of a new service, concerning the possibility for product customization by using generated design and fabrication data to drive CAD/CAM processes in the factory.

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Summarizing the experiments’ results, the following images show the potential of CAD/CAM technologies for expanding the design applications of pure cork agglomerates in architecture to match current interests and tendencies on: 

2D Shape: Current standard rectangular formats tend to limit the exploration of repetitive and orthogonal tiling strategies. By employing CAD/CAM processes, a world of infinite contour variation can be explored. [Fig. 6.01]



Surface texture: Without texture, the use of current products tends to produce only smooth surface facades. By employing CAD/CAM processes, digitally manufactured ornamental and performative (e.g., acoustic) textures can be explored, which gives an added value to the material. [Fig. 6.02]



3D Form: Being flat and having limited bending possibilities, current products tend to promote the covering of flat surface facades. By employing CAD/CAM processes, 3D components with variable geometries can be produced and applied, for instance, in buildings exhibiting complex shapes. [Fig. 6.03]

By diversifying the range of commercial products in pure cork agglomerate and offering a new service based on CAD/CAM customization, the cork industry has the opportunity for adjusting its role as a material provider for the contemporary architecture and building construction world. The combination of the digital expansion of its material design possibilities with the recent and increasing exploration of its facade applications can approximate pure cork agglomerate to the most sophisticated design interests and disciplinary discourses of contemporary architecture.

Nonetheless, it should be underlined that the present work does not exclude applications of the existing standard products in pure cork agglomerate but it expands its market potential towards new applications with new commercial and architectural attraction. Given that Portugal is the world leader in the cork production industry, such a potential can have a significant impact on the local industry and economy.

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2D SHAPE

EXISTING CONDITION:

Standard products with rectangular shapes

Repetitive and orthogonal patterns

DIGITAL CONDITION:

Geometric contour freedom experiments

Custom solutions with irregular contours

Figure 6.01

possibilities for pure cork

Innovative 2D shape agglomerate products open up new applications in architecture.

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SURFACE TEXTURE

EXISTING CONDITION:

Standard products with flat and smooth surfaces

Building surfaces without texture

DIGITAL CONDITION:

Geometric surface freedom experiments

Custom solutions with variable textures

Figure 6.02 Innovative Surface Texture possibilities for pure cork agglomerate products open up new applications in architecture.

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3D FORM

EXISTING CONDITION:

Standard products with box shape

Building forms with flat facades

DIGITAL CONDITION:

Geometric formal freedom experiments

Custom solutions with irregular forms

Figure 6.03

possibilities for pure cork

Innovative 3D Form

agglomerate products open

architecture.

up new applications in

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Chapter 6 Conclusion

FUTURE RESEARCH DIRECTIONS

Finally, some concluding remarks should be made about other strategies for integrating CAD/CAM technologies in the production of pure cork agglomerate products. In the practical experiments presented in Chapter 5, there are two reminiscent ideas that should be highlighted, as they can stimulate further investigation on the subject.

On the one hand, besides the exploration of subtractive processes, the digital manufacturing of pure cork agglomerate products can also indirectly benefit from current developments at the level of additive fabrication and construction, formative fabrication and robotic assembly that are worth discussing. For instance, additive technologies such as contour crafting can potentially work with liquid materials containing pure cork agglomerate granules in their composition. Also, by milling or shaping metal molds with particular forms for the autoclaves, pure cork agglomerates with customized geometries can be produced, using the traditional, formative, steam boiling processes. Nonetheless, the freedom for continuous variation in the production is still limited because the mold design, though different, still encourages the production of repetitive elements. Finally, the use of robots for building irregular structures, like the brick work developed by Gramazio + Kohler1, can be also applied for manipulating and assembling standard pure cork agglomerate blocks. In any of these three scenarios, the building of forms and structures with pure cork agglomerate products can lead to the emergence of unforeseen geometries.

On the other hand, despite their evident contribution for opening up new material design possibilities, the use of subtractive fabrication processes at the end of the production chain still has some limitations, as discussed previously. A natural evolution of such development route would consist in spreading CAD/CAM technologies throughout the whole production chain, to introduce flexible specifications and operations in earlier production phases.

Such an enterprise would require the development of specific digitally driven

1

See 3.3.4, where the use of robotic assembly processes in architecture is presented and

discussed.

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equipments adjusted to the nature of the material and to its production processes. To illustrate this idea, two examples can be described:



System for producing variable granulate composition Departing from the notion that distinct cork granules sizes are used for producing different material densities, the first example foresees a digitally controlled system for selecting and depositing them in the autoclaves. With such system, different cork granule sizes could be deposited, layer by layer, in the autoclave, giving origin to the production of blocks with variable granulated composition. Moving away from the isotropic condition of pure cork agglomerate blocks, such products could be designed to accomplish more efficiently different performative roles (e.g., thermal and acoustics). When combined with the use of milling processes this system can also create alternative and customized texture effects.



System for producing variable forms The second example consists in the implementation of CNC reconfigurable molds within the autoclaves. Inspired by Sebastiaan Boers’s FlexiMold research work2, such adaptive system could indeed support the serial production of blocks with variable forms with no material waste. To improve the surface finishing quality of the boiled blocks, a CNC milling machine could be used for milling just a thin layer of material, to correct its final dimensions and to produce its final texture. In this case, the waste material produced in milling works would be radically reduced, because the form of the raw material, produced with the reconfigurable mold, would have a form already very close to the desired final one.

The following diagram summarizes the opportunities for introducing CAD/CAM technologies in the pure cork agglomerate production chain [Fig. 6.04]. Although such opportunities require complex interdisciplinary research to be developed and implemented, they will have the potential for unleashing increased customization, cost‐efficiency, and sustainability to the whole process.

2

See 3.3.3, where the use of formative fabrication processes in architecture is presented and

discussed.

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Chapter 6 Conclusion

FUTURE SCENARIO

Figure 6.04 Advanced scenario for integrating CAD/CAM technologies in the industrial

Granulation

Boiling

Finishing

Final Product Standard Customized

´

CAD/CAM CNC Technology

6.4

ENDING NOTE

Finally, it should be stressed to anyone interested in studying cork or any of its derivative products, independently of its disciplinary approach, that this thesis ends up with its initial belief in the local and global importance of researching this material today, reinforced.

Developed through an architect’s eyes, it was nevertheless inspired by precedent work from other fields. Therefore, if it becomes a stimulus for pursuing further interdisciplinary research on cork, it will have definitely accomplished one of its main goals.

production of pure cork agglomerate products.

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Illustrations Credits

Illustration Credits All graphic representations (e.g., drawings, photographs, renders) done by the author are identified in the list as “J. P. Sousa”.

The full description of the published sources cited in the credits can be found in each chapter’s “References” section.

Chapter 1 Figure 1.01 Figure 1.02 Figure 1.03 Figure 1.04

Works and images by J. P. Sousa (ESARQ‐UIC, Barcelona, 2002) J. P. Sousa, FAUP, Porto, 2008 (left) J. P. Sousa, ESAP, Porto, 2007 (center) J. P. Sousa & M. Malé‐Alemany, ESARQ‐UIC, Barcelona, 2003 (right) ReD, J. P. Sousa & M. Malé‐Alemany, Barcelona and Graz, 2004‐2005 J.P. Sousa

Chapter 2 Figure 2.01 Figure 2.02 Figure 2.03 Figure 2.04 Figure 2.05 Figure 2.06 Figure 2.07 Figure 2.08 Figure 2.09 Figure 2.10 Figure 2.11 Figure 2.12 Figure 2.13 Figure 2.14 Figure 2.15 Figure 2.16 Figure 2.17 Figure 2.18 Figure 2.19 Figure 2.20 Figure 2.21 Figure 2.22 Figure 2.23

J. P. Sousa Image from: Addis, 2007: 97 J. P. Sousa J. P. Sousa Image in the public domain at: http://commons.wikimedia.org/wiki/File:Crystal_Palace.PNG Image in the public domain at: http://commons.wikimedia.org/wiki/File:Architect.png Image from: Watson, 2006: 87 Image from (left): Watson, 2006: 114 Image from (right): Watson, 2006: 1094 J. P. Sousa Image under the GNU Free Documentation License at: http://commons.wikimedia.org/wiki/File:SketchpadBN.jpg Image from: Kemper, 1985: 40 J P. Sousa Image from (left): Lamers‐Schutze, 2003: 697 Image from (right): Piedmont‐Palladino, 2007: 106 J. P. Sousa Image from (left): Fernandéz‐Galiano, 2005: 165 Image from (right): Galli & Muhlhoff, 2000: 76 Image from: Van Berkel, & Bos, 1999: 122 J. P. Sousa Image from: Cohen 2005: 43 J. P. Sousa Image from (left): Zellner, 1999: 148 Image from (right): Zellner, 1999: 115 Image from (left): http://architettura.supereva.com/files/20030918/02_c.jpg Image from (right): Bonet, 2004: 73, 74 Image from (left): http://www.designboom.com/eng/interview/hanirashid.html Image from (right): Zellner, 1999: 134 Image in the public domain (left) at: http://commons.wikimedia.org/wiki/File:Piranesi03.jpg Image from (right): Garofalo, 1999: 68

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Figure 2.24 Figure 2.25 Figure 2.26 Figure 2.27 Figure 2.28 Figure 2.29 Figure 2.30 Figure 2.31 Figure 2.32 Figure 2.33 Figure 2.34 Figure 2.35 Figure 2.36 Figure 2.37 Figure 2.38 Figure 2.39 Figure 2.40

Illustration Credits1

J. P. Sousa J. P. Sousa, Barcelona, 2003 J. P. Sousa, Los Angeles, CA, 2005 J. P. Sousa, Barcelona, 2002 Image from (top): http://www.architekten­franken.de Image from (down): http://www.oosterhuis.nl J. P. Sousa, 2002 Image from: http://www.mateo­maparchitect.com Image from: Schmal, 2001: 98, 99, 102, 108 Image under the GNU Free Documentation License at: http://commons.wikimedia.org/wiki/File:Internet_users_by_country_world_map.PNG (left): J. P. Sousa, Graz, 2005 (right): J. P. Sousa, Beijing, 2008 Image from (left): courtesy of J. P. Duarte Image from (right): J. P. Sousa, Seattle, 2005 Image from (left): http://www.klein­dytham.com/project/architecture/leaf­chapel/1 Image from (right): http://www.serpentinegallery.org/Toyo%20Ito%202.jpg Image from (left): J. P. Sousa, the Netherlands, 1999 Image from (right): courtesy of Mark Goulthorpe J. P. Sousa, Ampuria Brava, 2006 J. P. Sousa, with thumbnails of works by Frank Gehry (concrete), Gustafson Porter (stone), Bernard Cache (wood), Herzog & de Meuron (metal) and Gramazio+Kohler (brick) J. P. Sousa J. P. Sousa

Chapter 3 Figure 3.01 Figure 3.02 Figure 3.03 Figure 3.04 Figure 3.05 Figure 3.06 Figure 3.07 Figure 3.08 Figure 3.09 Figure 3.10 Figure 3.11 Figure 3.12 Figure 3.13 Figure 3.14 Figure 3.15 Figure 3.16 Figure 3.17 Figure 3.18 Figure 3.19 Figure 3.20 Figure 3.21 Figure 3.22 Figure 3.23 Figure 3.24 Figure 3.25 Figure 3.26 Figure 3.27 Figure 3.28 Figure 3.29 Figure 3.30 Figure 3.31 Figure 3.32 Figure 3.33 Figure 3.34 Figure 3.35 Figure 3.36 Figure 3.37

J. P. Sousa Image from: Zeid, 1991: 15 J. P. Sousa, AutoCAD representation J. P. Sousa, AutoCAD representation J. P. Sousa, BCN Strips, Master project, Barcelona, 2002 Image from: Thompson, 1961: 299 J. P. Sousa, Flex_H, Master project, Barcelona, 2002 J. P. Sousa, Flex_H, Master project, Barcelona, 2002 J. P. Sousa, 2005 J. P. Sousa, IST‐UTL, 2004 Computer drawings by: ReD, J. P. Sousa + M. Malé‐Alemany, Graz, 2005 Photos by: Inês d’Orey, 2006 J. P. Sousa, Grasshoppers definition in Rhinoceros, 2009 J. P. Sousa, IST‐UTL, 2004 J. P. Sousa J. P. Sousa, Grasshoppers definition in Rhinoceros, 2009 Image from: Kolarevic, 2003: 280 Image from (left): Furtado, Oliveira & Moás, 2005.

Photo by (right): J. P. Sousa, 2008 Image from: Kolarevic, 2005: 118 Courtesy of António Teixeira.

J. P. Sousa, MIT, 2003 ReD, J. P. Sousa, M. Malé‐Alemany, Barcelona, 2005.

J. P. Sousa Table based in: Hopkinson, Hague and Dickens, 2006: 55‐79 J. P. Sousa, 2009 J. P. Sousa, IST‐UTL, TU Eindhoven and Porto, 2009 J. P. Sousa, MIT, 2003 J. P. Sousa, IST‐UTL, 2009 Table based in: Rhul, 1997: 69; Lesko, 1999: 5, 59, 69; Schodeck et al., 2005: 256‐268; Kula & Ternaux, 2009: 240‐ 243, 248‐251 Image from (top): http://www.oosterhuis.nl Image from (bottom): courtesy of Dennis Shelden, Gehry Technologies ReD, J. P. Sousa, M. Malé‐Alemany, Barcelona, 2004‐06 J. P. Sousa J. P. Sousa J. P. Sousa Table based in: Schodeck et al., 2005: 268‐284; Lesko, 1999: 5 Image from: http://w3.bwk.tue.nl/fileadmin/bwk/ade/workshops/optimal_forming.pdf Image from: Kolarevic, 2003: 126 Image from: Fernandéz‐Galiano, 2005: 94

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Figure 3.38 Figure 3.39 Figure 3.40 Figure 3.41 Figure 3.42 Figure 3.43

Illustrations Credits

ReD, J. P. Sousa, M. Malé‐Alemany, Bremen, 2005 Image from (bottom right): Kunsthaus Graz, 2005) J. P. Sousa, 2006 Image from: http://www.shimz.com.sg/techserv/tech_con1.html Image from: Gramazio & Kohler, 2008: 60, 99 Courtesy from Behrokh Khoshnevis www.d‐shape.com/d_shape_presentation.pdf

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Chapter 4 Figure 4.01 Figure 4.02 Figure 4.03 Figure 4.04 Figure 4.05 Figure 4.06 Figure 4.07 Figure 4.08 Figure 4.09 Figure 4.10 Figure 4.11 Figure 4.12 Figure 4.13 Figure 4.14 Figure 4.15 Figure 4.16 Figure 4.17 Figure 4.18 Figure 4.19 Figure 4.20 Figure 4.21 Figure 4.22 Figure 4.23 Figure 4.24 Figure 4.25 Figure 4.26 Figure 4.27 Figure 4.28 Figure 4.29 Figure 4.30 Figure 4.31 Figure 4.32 Figure 4.33 Figure 4.34 Figure 4.35 Figure 4.36 Figure 4.37 Figure 4.38 Figure 4.39 Figure 4.40 Figure 4.41 Figure 4.42 Figure 4.43 Figure 4.44 Figure 4.45 Figure 4.46 Figure 4.47 Figure 4.48

J.P. Sousa, Alentejo, 2008 Image from: http://earthtrends.wri.org/updates/node/224 Image from: http://www.apcor.pt/artigo.php?art=289 Image from: http://commons.wikimedia.org/wiki/File:RobertHookeMicrographia1665.jpg Image from: Gibson & Ashby, 1997: 457 Image from: Pereira, 2007: 39 Image from: J.P. Sousa, Sintra, 2007 Image from: Diderot, 1993, 453 (left): J. P. Sousa, “Made on Cork” exhibition, FAUTL, Lisbon, 2006 (right): J. P. Sousa, 2009 (right) Image from: AMORIM, 2006, 49 J. P. Sousa, “Made on Cork” exhibition, FAUTL, Lisbon, 2006 J. P. Sousa J. P. Sousa J. P. Sousa, “Made on Cork” exhibition, FAUTL, Lisbon, 2006 J. P. Sousa Image from (left): http://www.danielmichalik.com Image from (right): http://www.jaspermorrison.com J. P. Sousa J. P. Sousa J. P. Sousa Image from (left): http://www.simpleforms.pt Image from (center): http://www.the­home­project.com/research/research_cork.htm Image from (right): http://www.craftscouncil.org.uk Image from: APCOR 2009: 23 Image from: APCOR 2009: 24 J. P. Sousa, AMORIM Factory, Vendas Novas, 2006 J. P. Sousa, AMORIM Factory, Vendas Novas, 2006 J. P. Sousa, AMORIM Factory, Vendas Novas, 2006 J. P. Sousa, AMORIM Factory, Vendas Novas, 2006 J. P. Sousa, AMORIM Factory, Vendas Novas, 2006 J. P. Sousa, AMORIM Factory, Vendas Novas, 2006 J. P. Sousa, AMORIM Factory, Vendas Novas, 2006 J. P. Sousa, AMORIM Factory, Vendas Novas, 2006 J. P. Sousa, AMORIM Factory, Vendas Novas, 2006 Table based in: Amaral et al., 2004: 245.

Table based in: APCOR 2006: 23 Table based in: Pfundstein et al., 2007: 8‐15 Image from: http://www.isocor.pt Table based in: Pfundstein et al., 2007: 18, 19 Image from: APCOR 2006: 45 Table based in: Pfundstein et. al. 2007: 20 Table based in: Pfundstein et. al. 2007 J. P. Sousa, AMORIM Factory, Vendas Novas, 2006 J. P. Sousa, Coimbra, 2004 J. P. Sousa, Coimbra, 2004 J. P. Sousa, Coimbra, 2004 Image from: http://www.habitarportugal.org/ficha.htm?id=388 Image from: http://www.habitarportugal.org/ficha.htm?id=388 Image from: http://www.habitarportugal.org/ficha.htm?id=388 J. P. Sousa J. P. Sousa, with thumbnails of works by Frank Gehry (concrete), Gustafson Porter (stone), Bernard Cache (wood), Herzog & de Meuron (metal) and Gramazio+Kohler (brick)

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Illustration Credits1

Chapter 5 Figure 5.01 Figure 5.02 Figure 5.03 Figure 5.04 Figure 5.05 Figure 5.06 Figure 5.07 Figure 5.08 Figure 5.09 Figure 5.10 Figure 5.11 Figure 5.12 Figure 5.13 Figure 5.14 Figure 5.15 Figure 5.16 Figure 5.17 Figure 5.18 Figure 5.19 Figure 5.20 Figure 5.21 Figure 5.22 Figure 5.23 Figure 5.24 Figure 5.25 Figure 5.26 Figure 5.27 Figure 5.28 Figure 5.29 Figure 5.30 Figure 5.31 Figure 5.32 Figure 5.33 Figure 5.34 Figure 5.35 Figure 5.36 Figure 5.37 Figure 5.38 Figure 5.39 Figure 5.40 Figure 5.41 Figure 5.42 Figure 5.43 Figure 5.44 Figure 5.45 Figure 5.46 Figure 5.47 Figure 5.48 Figure 5.49 Figure 5.50 Figure 5.51 Figure 5.52 Figure 5.53 Figure 5.54 Figure 5.55 Figure 5.56 Figure 5.57 Figure 5.58 Figure 5.59 Figure 5.60 Figure 5.61 Figure 5.62 Figure 5.63 Figure 5.64 Figure 5.65 Figure 5.66 Figure 5.67 Figure 5.68 Figure 5.69

J. P. Sousa J. P. Sousa J. P. Sousa J. P. Sousa J. P. Sousa, LASINDUSTRIA, Oeiras J. P. Sousa, VETOR 3, Sintra J. P. Sousa, IST‐UTL, Lisbon J. P. Sousa, IAAC, Barcelona J. P. Sousa, IST‐UTL, Lisbon J. P. Sousa, IST‐UTL, Lisbon J. P. Sousa, IST‐UTL, Lisbon J. P. Sousa, IST‐UTL, Lisbon J. P. Sousa J. P. Sousa, LASINDUSTRIA, Oeiras.

J. P. Sousa, VETOR 3, Sintra J. P. Sousa, IAAC, Barcelona J. P. Sousa, Porto, 2009 J. P. Sousa, Porto, 2009 J. P. Sousa J. P. Sousa, LASINDUSTRIA, Oeiras.

J. P. Sousa, VETOR 3, Sintra J. P. Sousa, IAAC, Barcelona J. P. Sousa, Porto, 2009 J. P. Sousa, Porto, 2009 J. P. Sousa J. P. Sousa, LASINDUSTRIA, Oeiras.

J. P. Sousa, VETOR 3, Sintra J. P. Sousa, IAAC, Barcelona J. P. Sousa, IAAC, Barcelona J. P. Sousa, Porto, 2009 J. P. Sousa, Porto, 2009 J. P. Sousa, Porto, 2009 Image from: Visual Mill software interface J. P. Sousa J. P. Sousa, IAAC, Barcelona J. P. Sousa J. P. Sousa J. P. Sousa J. P. Sousa J. P. Sousa, IAAC J. P. Sousa, Porto, 2009 J. P. Sousa, IAAC J. P. Sousa J. P. Sousa J. P. Sousa, IAAC J. P. Sousa J. P. Sousa, IAAC J. P. Sousa, IAAC J. P. Sousa J. P. Sousa J. P. Sousa, IAAC J.P. Sousa J. P. Sousa J. P. Sousa J. P. Sousa, IAAC J. P. Sousa, IAAC J. P. Sousa, Porto J. P. Sousa, Porto J. P. Sousa, Porto J. P. Sousa J. P. Sousa J. P. Sousa, IST‐UTL, Lisbon J. P. Sousa, IST‐UTL, Lisbon J. P. Sousa, IST‐UTL, Lisbon J. P. Sousa, IST‐UTL, Lisbon J. P. Sousa, IST‐UTL, Lisbon J. P. Sousa J. P. Sousa J. P. Sousa, IAAC, Barcelona

Jose Pedro Sousa PhD Dissertation, IST-UTL

Figure 5.70 Figure 5.71 Figure 5.72 Figure 5.73 Figure 5.74 Figure 5.75 Figure 5.76 Figure 5.77 Figure 5.78 Figure 5.79 Figure 5.80

Illustrations Credits

J. P. Sousa, IAAC, Barcelona J. P. Sousa, Porto J. P. Sousa, Porto J. P. Sousa, Porto J. P. Sousa, Porto J. P. Sousa J. P. Sousa J. P. Sousa J. P. Sousa, Porto J. P. Sousa, Porto J. P. Sousa, Porto

Chapter 6 Figure 6.01

Figure 6.02

Figure 6.03

Figure 6.04

Image from (top left): http://www.isocor.pt Image from (top right): http://www.habitarportugal.org/ficha.htm?id=388 Image from (center left): J. P. Sousa Image from (center right): http://www.serpentinegallery.org/Toyo%20Ito%202.jpg Image from (bottom left): J. P. Sousa Image from (bottom right): http://www.faulders­studio.com Image from (top left): http://www.isocor.pt Image from (top right): http://www.habitarportugal.org/ficha.htm?id=388 Image from (center left): J. P. Sousa Image from (center right): http://www.marotte.fr Image from (bottom left): J. P. Sousa Image from (bottom right): http://www.designspongeonline.com/2005/01/dont­i­have­some­dishes­to­do.html Image from (top left): http://www.isocor.pt Image from (top right): http://www.habitarportugal.org/ficha.htm?id=388 Image from (center left): J. P. Sousa Image from (center right): J. P. Sousa Image from (bottom left): J. P. Sousa Image from (bottom right): J. P. Sousa J. P. Sousa

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Appendix A Summary of CAD/CAM Experiments with Cork

Appendix A

SUMMARY OF CAD/CAM EXPERIMENTS WITH CORK Reference list of the CAD/CAM manufacturing experiments with pure cork agglomerate, developed and illustrated in the Thesis

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E.0.1 Milling

Place: IST‐UTL

Technology: CNC milling

E.1.1 Contour Geometry

Place: LASINDUSTRIA VETOR3, IAAC

Technology: CNC laser‐cutting CNC water‐jet cutting CNC milling

E.1.2 Cutting Tolerance

Place: LASINDUSTRIA VETOR3 IAAC

Technology: CNC laser‐cutting CNC water‐jet cutting CNC milling

E.1.3 Design Test: Clover Panel

Place: LASINDUSTRIA VETOR3 IAAC

Technology: CNC laser‐cutting CNC water‐jet cutting CNC milling

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E.2.1 Step‐Over parameter

Place: IAAC

Technology: CNC milling

E.2.2 Step‐Down parameter

Place: IAAC

Technology: CNC milling

E.2.3 Speed parameters

Place: IAAC

Technology: CNC milling

E.2.4 Tool Geometry

Place: IAAC

Technology: CNC milling

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E.2.5 Design Test: Waving Panel

Place: IAAC

Technology: CNC milling

E.3.1 Design Test: CorkStruct

Place: IAAC

Technology: CNC milling

E.3.2 Design Test: 3D Panel

Place: IAAC

Technology: CNC milling

E.4.1 Design Test: Cork­Stoppers Panel

Place: FEYODESIGN

Technology: CNC milling

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Appendix B Computational Design Studies

Appendix B

COMPUTATIONAL DESIGN STUDIES Selected works from the Computer Aided Design II course. Through the use of AutoLISP programming language, a computational design approach was explored as a means to address architectural design problems in AutoCAD. School:

Professor:

IST-UTL, 2004

JosĂŠ Pinto Duarte

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Appendix B Computational Design Studies

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Appendix B Computational Design Studies

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Appendix B Computational Design Studies

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Appendix C Computational Design Studies

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Appendix C CAD/CAM Studies

Appendix C

CAD/CAM STUDIES Selected Works from the Design Fabrication course where different CAD/CAM technologies were explored in short assignments.

School:

Professor:

MIT, 2003

JosĂŠ Pinto Duarte

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Appendix D Published research Digital Technologies

Appendix D

PUBLISHED RESEARCH ON ARCHITECTURE AND DIGITAL TECHNOLOGIES First pages of the series of 12 articles monthly published in the Portuguese architecture magazine Arquitectura e Vida, between June 2005 to June 2006. These texts were written as a complement and result from the research studies conducted for this thesis, about the state of digital technologies in architecture.

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Appendix D Published research Digital Technologies