3D PRINTING IN ARCHITECTURE

3D PRINTING IN ARCHITECTURE EXPERIMENTING IN THE DESERT THESIS PROJECT BY MIHAI DRAGOS POTRA SUPERVISORS: Prof. INGRID PAOLETTI Arch. ROBERTO NABONI

POLITECNICO DI MILANO School of Architecture and Society Bachelor Degree Thesis 2013

Mihai Dragos Potra Matricola: 763932 Bachelor of Architecture and Urban Planning Course: Science of Architecture mih_des_max@yahoo.com

Supervisors: prof. Ingrid Paoletti arch. Roberto Naboni

TABLE OF CONTENTS

ABSTRACT

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THESIS

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METHODOLOGY

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1. A NEW HORIZON

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What is 3D printing and how does it works?

Evolution of the 3D printing technology Technology potential Gartner’s Hype Cycle for Emerging Technologies The ten principles of 3D printing Techniques Applications Potential economic impact by 2025 Constraints and Solutions Transmigrating to large scale design Current architectural examples and proposals

2. 3D PRINTING IN REMOTE AREAS Reasons and advantages Potentialities Stressful environments and self-adaptation Desert, outer space, Moon, Mars and beyond

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3. INQUIRY INTO NATURAL ROCK FORMATIONS 87 Erosion versus deposition Agents of transformation - the Honeycomb rock structure Desert caves

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4. INQUIRY INTO BONE PATTERN FORMATION Selective material distribution Wolff's law Combined technologies: 3D printing and computational design Topological optimization methods

5. PROJECT PROPOSAL - SAHARA

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Lessons learned 105 Project’s goal 107 Site 109 Climate 111 Scenario 113 Materials consideration 115 Requirements and general strategy 117 Advantages and disadvantages fghfghfdghfdghfdghgfhgfhfdgfdfh of 3D printing with sand in the desert 119 The 3D printing technology to be used, considerations 121 The 3D printing technology to be used, specific details 123 Water problem 125 Experimentation 127 Unit shelter 135 Solution 137 Robot 3D printer 143 Implementation 145 Perspectives 149

6. VISION The future of 3D printing My view

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BIBLIOGRAPHY

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THANK YOU NOTE

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ABSTRACT

We are living in exponential times. The technologies of today will evolve into more advanced technologies of tomorrow in just few decades or only few years with tremendous implication on our daily life. The exponential technological growth has been observable in information systems such as radio and movie technology, in the transistor capacity of computing devices and material sciences, robotics and artificial intelligence.

However, the major part of the construction system of today is still based on traditional manufacturing technologies and implementation methods. The system is outdated as there are many new alternatives that can contribute to a new way of creating architecture and in a more effective way. Rethinking of the strategical approach of building architecture is of a primary importance in our times as new needs require new strategies. On the other hand the increased power of computing devices has allowed a digital fabrication approach of whose potential has overpassed our possibility of physical fabrication.

The recent development in manufacturing technology based on the synchronization between the computer and the machine has created new opportunities to transmigrate the digital fabrication power to physical implementation of digital designs. 3D printing technology is one of these developments and it holds us a big promise in terms of customized complex geometries and automation process within a large spectrum of applications from small ordinary household objects to highly customized complex objects for key applications or even scaled for architectural application.

The following document tries to examine the basics of this technology and the transmigration process to architecture applications with a specific focus on the usability and implementation of this technology in remote areas.

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THESIS

The primary target of 3D printing technology is to print on-demand custom objects. This has one huge application, that is, for the technology to be used in remote areas, where the lack of available resources for human subsistence is a problem. The 3D printing technology in remote areas can create custom tools or replacement parts for broken ones and many other kinds of useful objects for these places. However its biggest potential in remote areas lies not in the tool manufacturing but in the architecture construction system.

That is, a 3d printer can create in advance a desert habitat by means of an automated process and local materials use. The energy required to implement and control such an operation is minimum as it requires only the energy for deployment of the printers on the site and the timely supervision of the printer’s functionality and solar energy absorption systems. Because a 3D printer makes no difference in the process of constructing a complex structure, the design of the desert habitat will be based on the optimum structural pattern in response to stresses and applied loads on it. It is an approach to the bone pattern generation principle known as Wolff’s law which states that the internal structure of a healthy bone will self-readjust in a pattern for an optimal response to the stresses it is subjected to. Based on this idea, a 3D printer can create a functionally custom reinforced architectural structure in the desert while using the local material which is, in this case an abundant one, sand.

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METHODOLOGY

The document starts with a research on the 3D printing technology in general, showing its current state, advantages and applications. Further on it examines the application of the technology in architecture where I try to give critical views and reasons for it, and present current and proposed architectural projects for 3D printing. From this research I realize that the biggest potential that 3D printing can have in architecture is in remote areas. Thus, I enter into a deeper inquiry of this specific application by giving also my critical views and showing currently done or proposed projects for remote areas. The remote areas have their own desert architecture, that is the natural rock formation, which can act as a source of iznspiration for the natural integration of a 3D printed project on the site. As in regards to the structure of the architecture, an inquiry into the bone pattern formation and topological methods helps us to consider a desert shelter building that has a structural integrity of a bone morphology with a minimum use of material. The document continues with the project proposal that represent a synthesis of the previous studies, reasons and critical reflection. The ending part represents a reflection on the 3D printing technology and its future societal transformative potential.

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A NEW HORIZON

PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

WHAT IS 3D PRINTING? The basic meaning of 3D printing is the ability to create objects by a process of layering in 3D dimensions. For analogy, a printed image is made by a sequence of lines which are 1 dimension objects. In 3D printing the lines are represented by planes that are two dimensional objects. However in physical reality, neither the lines nor the planes are 1 and respectively 2 dimensional since they all have a thickness. This thickness is what makes an image to appear full or a 3D printed object a continuous solid. Thus, the 2D planes are actually 3D layers. By variating the thickness, a less or higher resolution can be achieved.

Instead of printing with ink, 3D printers print with materials by a successive deposition in 3D layers that ultimately form a 3D object. The technical name for 3D printing is “additive manufacturing,� which in contrary to substractive processes does not generate waste.

Thanks to the advances in computing power, new design software and new materials, the development of 3D printing has been accelerated with a new interest in the technology.

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HOW DOES IT WORKS? There are several techniques of how 3D printing works, which will be discussed later. What we need to know is that there are currently two families of techniques: Selective Binding/Fusion and Selective Deposition. In selective binding/fusion, the printer uses a laser or binding solution to fuse/bind a granular/liquid substance into multiple 2D layers. The object created is always submerged into the raw material it is made of. In Selective deposition raw material is deposited into layers onto a platform. The raw material is located outside the printed object. It is then fed to the printer that heats it to make it viscous. The extruded material hardens as it makes contact with the last deposited layer, thus forming a 3 dimensional object.

The movements of the printer’s head are automatically controlled by a computer in a specif pattern that represent a cross section of the desired object.

This has tremendous implication on the printing process since it is unrestricted by the complexity of the shape to be printed. However there is one important difference on this aspect when it comes to consider one of the two families. The selective fusion can be used to literary print any imaginative shape since its raw material will most of the time(especially if it is powder) support the solidified object by surrounding it in all points. The selective deposition can not do this and a printed object will have to support itself or use temporary printed supports if its shape is not meant to provide it by itself.

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Selective Fusion

Laser source

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Elevator

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Vat

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Layered parts

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Material

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Selective Deposition The motor draws the plastic filament, melts the plastic and pushes the melted plastic through the nozzle

Filament

Print nozzle

1 A laser source sends a laser beam to solidify the material 2 The elevator raises and lowers the platform to help lay the layers 3 The vat contains the material usedto create the 3D objects 4 The 3D object is created ad partsare layered on top of each other 5 Advanced 3D printers use one ormore materials , including plastic, resin, titanium, polymers and even gold and silver

The printer lays down succesive layers of liquid powder, paper or metal material and builds the model from a series of cross-sections

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

EVOLUTION OF THE 3D PRINTING TECHNOLOGY 1984

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THE BIRTH OF 3D PRINTING

BUILDING PARTS LAYER BY LAYER

ENGINEERED ORGANS BRING NEW ADVANCES TO MEDICINE

A WORKING KIDNEY

OPEN SOURCE COLLABORATION WITH 3D PRINTING

SLS LEADS TO MASSCUSTOMIZATION IN MAUFACTURING

THE FIRST SELF-REPLICATING PRINTER

Charles Hull, the cofounder of 3D Systems, invents stereolithography, a printing process that enables a physical 3D object to be created from digital data. The technology is used to create a 3D model from a picture.

The first stereo lithographic machine (SLA) is produced by 3D Systems. The machine used an UV laser solidifying p h o t o p o l y m e r, a viscous liquid to make threedimensional parts layer by layer.

The first lab-grown organ is implanted in humans when young patients undergo urinary bladder augmentation using a 3D synthetic scaffold coated with their own cells.

A m i n i a t u r e functional kidney is produced that is able to filter blood and produce diluted urine in an animal.

Dr. Adrian Bowyer at university of bath founds RepRap, an open-source initiative to build a 3D printer that can print most of its own components. The vision of this project is to democratize manufacturing by cheaply distributing RepRap units to i n d i v i d u a l s everywhere , enabling them to create products on their own.

The SLS (laser sintering machine) becomes viable and opens the door to mass customization and on-demand manufacturing.

RepRap project release Darwin, the first self-replicating printer that can print the majority of its own components

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The first machine capable of printing in multiple materials and densities is created

2009

2011

2012

DIY CO-CREATION SERVICE LAUNCHES

MAJOR BREAKTHROUGH FOR PROSTHETICS

DIY KITS FOR 3D PRINTERS ENTER THE MARKETPLACE

FROM CELLS TO BLOOD VESSELS

FIRST 3D PRINTED ROBOTIC AIRCRAFT

WORLD’S FIRST 3D PRINTED CAR

3D-PRINTED PROSTHETIC JAW IS IMPLANTED

Shapeways launches a cocreation service and community allowing artists, architects and designers to make their 3D designs as physical objects inexpensively.

The first 3D prosthetic leg is produced with all its parts: knee, foot, socket, etc, printed in an unitary complex structure without assembly.

M a k e r B o t Industries, an open-source h a r d w a r e company for 3D printers, starts selling DIY kits that allow buyers to make their own 3D printers and products.

A rD bioprinter is used to print the first blood vessel

3D printing allows the plane to be built with elliptical wings, a normally expensive feature that helps improve aerodynamics and minimizes induced drag.

Urbee has a complete 3D printed body and it’s designed to be fuel-efficient and inexpensive.

A 3D printer was used to print a customized threedimensional prosthetic lower jaw.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

TECHNOLOGY POTENTIAL Like any technology that was at some point invented, 3D printing has it’s own potential. A new technology may appear on a previous substrate that reaches a developing point that favors the development of a new technology. Metallurgy allowed the creation of mechanical tools to create metal wires that allowed electricity transfer to operate electrical machines which in turn created circuits to create more complex machines like a computer that allowed 3D Printing to come into existence.

Often a new technology may appear before it’s time and when the time is right, it needs only a trigger to manifest it’s potential.

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It is easy to make statements like “3D printing - the next industrial revolution!”, or “3D printing, a paradigm shift!”. But is it like this? Is 3D printing a world changing technology?

Aren’t we forgetting something? Like the fact that the technology itself is pretty much dependent on our interest in it? Having seen the paced acceleration in the development of the technology during the last years I have no doubt that the interest is there and is growing and so does the technology.

3D printing is not new at all, it’s first baby steps were taken in the mid 80’s. However it didn’t soar like a true visible technology until recently. Some of the reasons might be the limitations of use due to the patent attribution and the high price of computers at that time. For 2 decades it remained almost silent, like a peripheral technology. However the old patents are now expiring and with the new powerful design tools and an a new bunch of young entrepreneurs and experimentalists, the technology is now tested on new grounds.

3D printing opens us new doors. It will disrupt manufacturing and business as we know it, as it enters the hands of regular people. It promise us control over matter. People will have the power to create their products when and where they need in a push of a button(or maybe two). Yet, when you have the power to create you can also destroy. Every technology is as good as people using it. A 3D blueprint of a gun reaching the hands of individuals around the world might not sound as the best idea. Neither creating unregulated or toxic drugs nor swimming in a sea of quickly discarded print-on-demand plastics, while the stem cell controversy might seem nothing in comparison with ethical challenges that bioprinting is imposing.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

GARTNER’S HYPE CYCLE FOR EMERGING TECHNOLOGIES According to the world’s leading information technology research and advisory company, Gartner, every emerging technology follows what is called a “hype cycle.” The hype cycle follows a new technology from early adoption through its growth to where it reaches “mass media hype.” After that comes some disappointment as the bloom comes off the rose and the media walks back some of its previous puffery. Then after a steep decline in hype, when about 5% of the potential audience has finally fully adopted the technology, a bit of media buzz comes back as they see the solid commercial growth of a mature technology.

3D printing first appeared on the chart in 2008. Since then it followed a rise on the curve and got at its maximum in 2012 when it meet a large flux of mass media attention. However the report made reference more to the hobbyist sector than to the consumer one. From 2013, the report makes a distinction between the consumer 3D printing and the enterprise 3D printing, of which the later is shown as reaching to the state of a mature technology in a time window of 2 to 5 years.

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As of July, 2013

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2012

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THE TEN PRINCIPLES OF 3D PRINTING In their book, ”Fabricated: The New World of 3D Printing”, Hod Lipson and Melba Kurman identify 10 basic principles that illustrates the potential of 3D printing technology.

These principles outline a different approach to the way we create objects and have high implications on our manufacturing production system.

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1 - Manufacturing complexity is free: printing a complex object does not require more time, money and skill as a simple one.

2 - Variety is free: different geometries can be printed by the same printer each time it operates, which differs from the traditional factory machines that needs re-calibration for each new type of object to be manufactured.

3 - No assembly required: a traditional multi-parts object can be 3D printed in one shot as a single object thus eliminating the so long time used assembly line. As some components of a product can be produced continents away, this feature can save time and cost on labor and transportation, and making the production more sustainable.

4 - Zero lead time: the possibility of on-the-spot manufacturing can engage local companies and individuals to print custom objects on-demand.

5 - Unlimited design space: a printer can create such shapes that would have been very hard or impossible to create with the traditional machines, reaching the possibility to create shapes that until now existed only in nature.

6 - Zero skill manufacturing: calibrating a printer to create an object requires less operator skills as the process is almost fully automated. This has high advantages for people in remote areas or extreme circumstances.

7 - Compact, portable manufacturing: a 3D printer has more manufacturing capacity than a traditional machine as it can print objects as big as its volume or larger if the printhead is attached to a robotic arm.

8 - Less waste by-product: as it is an additive manufacturing technique, zero or less waste is produced.

9 - Infinite shades of materials: one of the holly-grails of 3D printing is to print with multiple materials to create new type of materials and geometries with new proprieties and behaviors.

10 - Precise physical replication: an object can be scanned and printed in the same shape. Any scientific, medical or design intervention can be made on the replica, thus leaving the original unaltered.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

TECHNIQUES 3D Printing makes use of several techniques which differ by factors as speed, cost, material, size, complexity etc. Different applications require different techniques but the basic principle of layering an object remains the same. As I mentioned earlier, there are two big families of printers: selective deposition and selective fusion/binding. The first category consists of printers that extrude, squeeze or spray raw material while the second one fuse, binds or glue raw material.

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SELECTIVE DEPOSITION TECHNIQUES - Fused Deposition Modeling (FDM): was invented in the 80’s and is the most common type of 3D printing for home use.

It usually works by extruding a plastic filament through the printer’s head and laying it down in multiple layers on a support. One advantage of these printers is that they have a relatively low cost, they are easy to use and assemble, thus making them most suitable for home use. Another good thing about this type of printers is that they can extrude any material that can be extruded including chocolate, cheese or even stem cells to create living organs. Yet it’s biggest strength is also it’s biggest weakness, as it can not work with materials that can not be created or extruded under specific conditions like molten metal or glass which requires a different type of printer.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

- Contour crafting: it is a fused deposition modeling technique that is mostly used for large scale designs with possible implementation in architecture. It is similar to a desktop printer with the difference that it can use architecture construction materials such as concrete and clay while the printing head can be attached to a robotic arm or a mobile printer for a more flexile reach to the printing area. The advantage is that it represents a cheap alternative to the traditional concrete construction approach in which the concrete is poured in a pre-exiting mold. While it is advantageous for vertical wall contour construction, it has a deficit in horizontal concrete slab construction which will still require a prior mold.

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- PolyJet printing: was introduced in the year 2000 and is a technique that makes use of both the major families of 3D printing processes. It uses a liquid photopolymer type of plastic that is sprayed through the printer’s head onto a surface while an UV light solidifies the photopolymer in a 3 dimensional object. It’s advantage consist in the printing resolution and it’s speed, by printing thin layers as thin as 16 microns. It can print as well in multiple materials by using several print heads at once. It is best for use for industrial and medical applications where speed and precision plays an important role. The disadvantage is that the photopolymer is a highly specialized, expensive plastics that respond to UV light and unlike other plastics, it is fragile and brittle which limits their applications.

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- Laser Engineered Net Shaping (LENS) also known as Directed Energy Deposition: it was among the first 3D printers to use metal. It can spray a metal powder onto a base substrate.

Some of the power will slide over but some will be fused by a laser when it reaches the focal point of the laser, thus forming successive additions to the base metal. Multiple nozzles can be used to spray different metals such as titanium and stainless steel thus forming an alloy type of metal that is hard and durable. It can consider as well the ratio of each metal by spraying from different angles thus creating a graded metal.

It is most used in aerospace and automotive industry and good for creating titanium turbine blades with internal cooling channels.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

- Laminated object manufacturing (LOM): The machine does not use a printing head but instead it uses thin sheets of paper, plastic or metal to laminate them into a 3D object. The computer defines the movements of a laser which cuts the surface into a cross section.

When one layer is done, a new sheet is overlapped on the previous one and the process repeats. At the end, when all the sheets have been cut out, a pressing force is applied to fuse all the cross sections into a solid object. This process is a combination between additive and subtractive manufacturing as it involves remaining parts of the sheets after the cuts out.

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PRINTERS THAT FUSE, BIND OR GLUE - Stereolithography (SL): One of the oldest methods of 3D printing, is using a UV-sensitive liquid photopolymer that solidifies in contact with a laser beam. The printer contains a tank filled with this liquid and a laser traces the shape of the cross sections of an object that is attached to a vertically moving supporting platform. After the first layer is done, the platform is lowered by a small distance and while the object sinks, the liquid floods its top part.

The object can be as well suspended by the platform and risen out of the liquid In this case the laser beam works from below and the object is created from the top.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

- Laser Sintering (LS): Is a technique similar to Stereolitography but instead of using a liquid it uses a powder material, usually metal. It starts with a single layer of powder that is added into a tank. Then a laser, following a digital design, melts the powder in specific locations to create cross-sections of the object. After the first layer is done, a roller brush up a new layer on top of the last one and the new melted portions will fuse with the old ones.

One advantage of this technique, in comparison with the liquid polymer, is that the powder material acts as a built-in support for the created object. At the same time many materials can be obtained in powdered form that can be used in this process.

The disadvantage is that usually the surface of the object tends to be porous instead of being smooth.

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- Powder bed and inkjet head 3d printing also know as simply Three Dimensional Printing (3DP): Maybe the most related technique to traditional 2D printing, is also one of the cheapest and adaptable technique. The difference between the laser sintering is that here the printer uses a liquid binding agent that binds or glue the powder material into a solid state. Among the advantages is that color can be added to the inkjet and a wide variety of powder materials can be used, including powdered clay, glass and metal, that needs to be later sintered in an oven. The disadvantage is that the resolution is lower, it’s hard to make very thin layers and the surface of the printed objects tend to be a rough one.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

- Electron Beam Melting (EBM): involves a high energy electron beam that melts a metal powder . It is managed by electromagnetic coils that control the electron beam in an extremely fast way with high accuracy and high melting capacity. The process takes place in vacuum chamber for reasons of maintaining the chemical properties of the material. For each new layer the electron beam heats the entire powder bed to an ambient temperature that is best for the material used. This will provide a uniform internal structure. The resultant object is fully dense, void-free, and extremely strong and it doesn’t require additional thermal treatment.

The common metal used is titanium and the technique is used in orthopedics and aerospace industries.

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- Two-Photon Lithography: it is based on a multiphoton absorption process of a material whose transparency is at the same wavelength as the laser beam. It works with multiple pulses at high energies. The molecules contained in the resin material are activated by the laser beam and induce a chain reaction in other components of the resin, called monomers which are then turned into a solid. In this process. The activation occurs only when two photons of the laser beam are absorbed at once. A big difference from the standard 3D printing technology where a layer is created on top of the previous one, is that the solidification can occur in any place of the liquid resin at the focal point of the laser. It is most suitable for creating nanoscale 3D printed structures.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

SUMMARY OF MOST COMMON TECHNIQUES USED

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NEW 3D PRINTING TECHNIQUES - Bioprinting: It’s a new research area in science and medicine that has the aim of creating living tissues and organs. The process starts with printing with a bio-ink that contains living cells. The bio-ink is deposited in successive layers in the shape and texture of the required tissue. A Bioinert hydrogel can be added as a support structure for a vertical layering or as fillers to create a pattern that mimics the features of the original tissue.

It has tremendous implication in food engineering, like creating meat, and as the technology will improve, in creating full organs.

The first step in creating meat is to collect stem cells from an animal. Stem cells are cells that are able to replicate themselves many times and can transform in any other type of cell of an organism. They are added to a bio-ink and then printed in the supporting structure to develop themselves.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

- Liquid metal droplet stacking: It is an experimental technique that uses an alloy metal made of galium and indium. Galium exists in a liquid state at room temperatures and when in combination with Indium reacts to the oxygen contained in the air to form a very thin skin, of about 1 nm thick, that retains the shape of the metal. By stacking droplets of this liquid metal on top of each other, they bound to each other to form a single structure. While the strength of their surface is enough to maintain their weight, if a shock is applied, they can easily break. As galium is already used in microelectronics, the best use of this technique is in connecting 3D circuits.

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- Freeform Printing: Suspended Depositions : In this process a light-curable resin is deposited into a gel-filled print bed that acts as an omnidirectional support structure. The printer’s head is attached to a robotic arm that can move freely in the space.

The difference is that in this case the movements of the arm are determined by 3D vectors instead of a bidimensional contour tracing. This allows for accessibility in any point of the object while the transparency of the gel allows for visibility from any angle of the suspended object.

The process can have as well an undo function. Depending of the material injected into the resin, if needed it can be removed via suction or scooping.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

- Freeform Printing: MATAERIAL - Anti-Gravity Object Modeling: The process involves the extrusion of a polymer in the shape of spatial curves based on the movements of a robotic arm. The material used is a combination of two polymers that hardens in contact with air. The generated curves are though enough support themselves, can be joined together and can be attached to any surface in any position. The difference between this technique and others is that the object is made up of successive curves rather than successive layers and can be formed from any direction with the possibility of additions, connections and extensions in an unlimited space.

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- Freeform Printing: Custom Multi-Fiber Extrusion ---- Computer Numerically Controlled Silk Cocoon construction (CNSilk): The technique is based on the silk formation process in a silk worm cocoon. In an experiment a computer tracked the movements of a silk worm while constructing its cocoon and translated the data to a printer attached to a robotic arm. The data will be used to construct a pavilion with the dimensions of 366 x 366 cm. The arm will deposit silk fibers and a gluey “matrix�. The matrix will most probably be made of a new type of material called shrilk which is made of discarded shrimp shells and proteins derived from silk. Shrilk is a thin and transparent material, flexible and strong as aluminum, and yet, it has half the weight and it is biodegradable.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

- Free Form Printing: Stone Spray It is a process similar to Direct Energy Deposition technique, but instead of using metal powder and a laser beam to fuse it, it uses sand or soil sprayed through a nozzle, while another nozzle sprays a liquid binder. As they hit a surface, the sand is solidified into a sandstone kind of material that is forming a desired structure. The nozzle is attached to a robotic arm whose movements are controlled by a human, thus the final design of the structure will be determined within the printing process by the human.

The robotic arm can move freely and due to this the material can be deposited from many different directions, similar to suspended deposition technique.

This technique takes full advantage on the local materials, like sand, it is fast and cheap and appropriate for big scale design up to architectural scale.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

- Solar Sintering: The difference between laser sintering is that it involves the use of sun power to create 3D printed structures. A bed of sand is laid down in a tank and a fresnel lens focus the sunlight into a point on the surface of the sand to fuse it. The system is using a camguided system to cut or fuse materials as sand, in layers. The end result is a 3D printed glass object made of multiple layers. As the printer works with solar energy both for it’s operation and for the material fusion, and a the same time the materials are found locally, the technique can be considered a high sustainable one and optimal for creating customized tools and pots out of the local material.

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APPLICATIONS 3D printing technology has been used in different applications since its birth. However, these were restricted and limited by the infancy of the technology and used only for specific and high selective domain applications. This is about to change as we are now entering a new manufacturing era. During the last years, it found its way to a new set of applications ranging from small individual needs to large scale manufacturing industries and improved its performance to adapt to new needs that our society is facing today.

The most embraced application of 3D printing until now was in Rapid Product Prototyping and pre-production mould making processes. Today, the 3D printing technology is taking a big leap in Direct Digital Manufacturing (DDM) with ramifications in a wide spectrum of sectors. DDM benefit of a great advantage over other manufacturing processes as it can produce final products for end-users directly from a digital file. The printed objects are suitable for direct industrial, business and home use depending on the technique and material use

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The spectrum of 3D printing applications include arts, construction, aerospace and motor industries, fashion, replacements parts, food and medical sciences. The focus is now on the medical research, food sector, household items and replacements parts. The aim of the medical research is to print full functional organs that will eliminate the waiting time for a donor, while in the food sector the aim is to create meat by a bioprinting process thus putting an end to the present meat production industry that is currently very unsustainable. The same principle can be applied in the case of replacements parts, so that instead of buying a new product because the old one has a broken part, you just print a new replacement part.

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POTENTIAL ECONOMIC IMPACT OF 3D PRINTING BY 2025 Source: McKinsey Global Institute Analysis - MGI Disruptive technologies Full report May2013

In the MGI Disruptive technologies report it is estimated that 3D printing could have an economic impact ranging from $230 billion to $550 billion per year within sized application by 2025. The biggest economic impact will come from consumer use followed by direct manufacturing of end products and tool and mold manufacturing. From the consumer part, it is expected that the impact will be represented by certain consumer product categories which include toys, jewelry, accessories, footwear, ceramics and simple apparel. Most of the consumers will have access to 3D printing either by owning their own printer either by printing at a local store or ordering online. It is estimated that consumers will 3D print 5 to 10 percent of these products by 2025. The saved cost by self 3D printing this products, despite the higher material cost, will range from 35 to 60 percent. The consumers can either pay for the designs or download them for free legally or not. This rises the problem of author rights, as many digital models can be downloaded illegally for free and shared among the users.

Other might be experimented or less experimented digital model designers that will create their own products. In any case there will be the cost of the material and the limitations of the printer that will ultimately decide the type and quality of product the consumers can self-print.

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CONSTRAINTS and SOLUTIONS The 3D printing technology, besides its many advantages and vast potential applications, has it own limits. The purpose of 3D printing is, as the name says, to print 3D objects. By definition, printing, means one layer at a time, which imposes a longer time to create an object, and depending on the size, material and quality of the object, a higher cost. This is the reason why is not suitable for large scale manufacturing nor for large scale designs.

However with new research in this technology, today the technology makes the transition to large scale manufacturing in the shape of individual possession of home or local 3D printers that put to a shake the industrial centralized manufacturing and the big product businesses.

The cost can be equilibrated by an intelligently use of material by creating new geometries where less material is deposited in such a pattern that will confer the object an equal or higher performance than a traditional manufactured one.

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• Affordability: Currently, the costs of 3D printers ranges from 500 $ to a few thousands $ for househould use and from 15 000 $ to 300 000 $ for commercial uses. These prices are rapidly falling down as the 3D printing market is extending and the technology reaches the hands of the individuals. The self involvement in the improvement of this technology can further lower the prices and having the option to buy a 3D printer kit or just parts to make yourself a printer can be a money saving solution. On the other hand, if a printer can print most of its parts, it will mean that the major price will be determined only by the material that is used for printing.

• Availability and cost of materials: There are few common materials that 3D printers can work with. Currently these include plastics, ceramics and certain metals. However the materials used in 3D printing are highly expensive as they need to be powdered or meet certain properties for the machine to be able to print them. New materials are introduced every day to the world of 3D printing and as the printers will know how to operate with them, they will become more available to the general public.

• Time: It is one important element to consider since most 3D printers operate on a layering basis that depending on the resolution, size and technique, can take more or less time to print. This is the reason why the majority of 3D printers today print only small customized objects. What we should consider in this case is that a complex object can actually take less time to manufacture by 3D printing, since the technology does not make any difference between a simple and complex one. With contour crafting, time is less of a problem for large scale objects as it can actually be a faster process than a traditionally formworks and mould making one. Then multiple printers or a printer with multiple printing heads printing simultaneously and maybe even with multiple materials, can be a time saver.

• Mobility: Until now, almost all 3D printers have, or at least in the traditional sense, are represented by a box inside which the printer head is sliding across some rails. This means the object is defined by the movements of the print -head and is usually constructed by vertical layering. New types of 3D printers like the antigravity printer or spray stone printer are print-heads attached to a robotic arm, which has as well its own movements limitations, but are better when it comes to print objects larger than themselves and from a multidirectional intervention.

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• Dimension: Most 3D printers are constructed and calibrated to create small customized objects. But in comparison with the traditional manufacturing machines, 3D printers have a lower footprint ratio since the printed object can be almost as big as the printers themselves. One thing to consider is the exponential rise of the cost of material and time used when it comes to bigger objects. The increase in dimension means an increase in time and material by a factor of 3. A 3x3x3cm object requires 27 cm^3 of material and time.

An object twice as large needs 6x6x6 = 216 cm^3 of material and time. The ones that are able to print objects larger than themselves are usually attached to a robotic arm that is controlled by a computer and sometimes by a human that makes live adjustments to the design of the object. In this case the layering/deposition of material can take place in an infinite space and is limited only by the reach of the robotic arm.

• Precision: Within the industrial engineering process a high precision, mass and speed can be achieved. This is not the case with 3D printing. The precision in 3D printing depends on the technique and materials used. Since it works in layers, the resolution of each layer represent the maximum precision that the printer can achieve. The smaller an object is, the more suitable for high resolution layering is.

Some techniques like metal laser sintering can achieve low customized highly performance objects that can be used in aerospace industries, or like two-photon absorbtion that can create nanoscale structures.

• Strength: Simply layering does not generate a load-bearing or tensile resistant structure unless is it configured in such a way that it is able to meet the object’s requirements. One of the disadvantages of layering is that the stresses inside the structure will always depend on the direction of layering. One solution is to use fibers extruded in different directions as reinforcement agents. The type of material is also important but more important is the deposition technique. A laser sintering can fuse metal powder into a solid object that is tough enough for critical application. However this is costly and can become even more costly if more material is needed. The solution is found in the 3D printing ability to print in complex geometries to create structural customized behavioral patterns that can attribute to the object the same or even higher strength with less material, time and cost. Then the ability to print with multiple materials at once to create new degree variated material composites can open a new door to the material sciences.

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TRANSMIGRATING TO LARGE SCALE DESIGN First, in order to make the transition to large scale printable structures, there are few things we need to consider: - why would 3D printing be a better way to construct such a large structure instead of using existing technologies?

- how can 3D printing be implemented in a reasonable way for architectural purposes?

- what materials can be used at the present time?

The current building construction sector has its limitations as regards to its ability to create customized geometries and responsive materials. Here is where 3D printing plays it’s biggest role as it is not only a better way but a very powerful tool of linking the real physical world with the digital one. We must agree on the observation that the software capabilities of digital representation have evolved way beyond our capabilities of physical representation with traditional techniques without requiring large resources time and costs, and is up to the additive manufacturing process that this complex digital models can be implemented in a reasonable way as it makes no difference in the degree of complexity. Thus when we are talking about 3D printing in architecture we are not talking about building 4 planar walls and a roof on top, but about building customized complex geometries that respond to environmental and human factors all by themselves without the requiring of additional

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maintenance systems to complement the required needs of the building. In this sense, the building is selfsufficient as an unitary system created in one print job. The materials can be no different than the traditional building construction ones like concrete, steel, plastic and even paper but the ability to reconfigure them by selective deposition into metamaterials is what makes the 3D printing use so special.

For now, 3D printing in architecture is in its experimental phase, there isn’t, as of this moment, a real habitable building made by 3D printing alone, but smaller scale structures that are made either by 3D printing alone, either partial printed, printed components or in a more doubtful sense, are made by similar techniques but not to classified as real 3D printing. In any case they demonstrates the potential of using this technology in architecture for a larger spectrum of building choices.

Problems: Currently, most 3D printers are made to print small customizable objects that are not bigger than the printer’s body size, although the objects can take up to 90% of the volume occupied by the printer’s body. However the problem is found in the printer’s body itself since this is usually not larger than a fridge. Thus, in a general way, the printer will be restricted by its volume, printing technique and the materials it can use. Resizing this type of printer, which we can call it a control volume printer, to fit larger structures or even buildings is possible but might not be an efficient way of manufacturing. That is because of the following reasons: 1 - the printer’s body is a fixed element, and having to be transported on site, to create a building smaller than itself, especially in low access locations, might create some problems.

2 - the printer must be stiff enough to sustain it’s own weight, resist wind forces and keeping the required precision while printing.

3 - the difficulty to use the type of printers that fuse or bind materials from an existing container containing the material will be direct dependent on the printer size. The larger the container, the larger the mass and pressure of material it has to sustain.

4 - if the selective deposition printers are more pragmatic than the fusing ones in this sense, they do not benefit of the same freedom as the previous ones in terms of shape optimization, which means it would be nearly impossible to print in a selective deposition technique an horizontal surface as a slab for example.

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Alternatives There are many alternatives to build architectural structures by using the 3D printing technology and many techniques of this technology are proposed every day. The fact is, sooner or later, the technology will reach to a point where entire buildings will be 3D printed. Until that day, which might come in just a few years, there are full and partial solutions to the above problems of 3D printing at large scale design.

1 - a large printer can be assembled on-site and if one printer, no matter if large or small, is already implemented on the site, it can print components for new printers that are to be assembled on the spot as well, saving time and money that otherwise would have been taken from transporting them from far distances.

2 - having the large printer’s structure made of a customized stress responsive body generated through a digital simulation process and printed in parts by another 3D printer that can actually construct this customized body.

3 - rise along the structure a fixed sized container, maybe not more than few cm deep, on which a thin new layer of material will be added for each fusion application. As the layer will be done, the bottom of this container will open up and the new solid layer will overlap the last fused layer of the structure and be permanently bounded to it either by a special glue only or the special glue plus reinforced steel bars that pass through a perforated pattern of the layers. You can imagine it as sheets in a metal rings notebook.

4 - instead of a control volume printer, to use a printer attached to a robotic arm which can move freely in the space “outside� it. The arm, depending on its size, locomotion and extension capability, can have access in almost every point of the structure thus it can retouch and fix things that were omitted during the construction process or damaged in time.

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CURRENT ARCHITECTURAL EXAMPLES AND PROPOSALS

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FabClay is a 3D ceramic printing project launched by barcelona-based Sasha Jokic (Serbia), Starsk Lara (Colombia) and Nasim Fashami (Iran) aiming to explore a new digital fabrication system. It is a robotic additive manufacturing processes using industrial a Kuka robot and new 3D printing technology.

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Designers Petr Novikov and Saša Jokić extrusion studies - Advanced Institute of Catalonia “Antigravity System”

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A research project Stone Spray led by Petr Novikov, Inder Shergill and Anna Kulik was carried out in the Institute for Advanced Architecture of Catalonia, Barcelona.

Stone Spray' is an on-site robotic 3D printer that uses a jet spray system to deposit the mix of soil and liquid binder to construct architectural shapes.

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Ginger Krieg Dosier, an Assistant Professor of Architecture at the American University of Sharjah in the United Arab Emirates, has envisioned a new material to build transmission towers in the UAE desert, and it is based on the rapid growth of bacteria. She bases her idea off of the specific germ Sporosarcina Pastuerii, which is a common soil bacteria that can create a “biocement� material that has the ability to fuse with sand and, through a process known as Calcite Precipitation (MICP), creates a material that is sustainable, unlike wood, and unexpected, unlike concrete. The process is as such: the bacteria is grown and then fed into a 3-D printer, which will meld the bacteria with graded sand. This mixture is then molded into units, utilizing local industrial facilities to create the units with casts. This method of material creation yields little waste, and allows for accuracy throughout the building process, with units being created thicker or thinner depending on what each area of the tower needs.

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The D-Shape printer works by extruding liquid adhesive through hundreds of small nozzles onto the bed of sand. The mixture contains a catalyst the makes the adhesive more quickly bind to the sand. After four passes, the printed layer solidifies. Fresh sand is sprinkled on top and the robotic arm is recalibrated so it can deposit another layer of adhesive on top of the first. It takes about a day for the printed walls to solidify.

According to Enrico’s website, the adhesive is strong and can substitute for iron as a structural reinforcement. The artificial stone printed by the D-Shape printer could be made of any kind of sand and it’s stronger and cheaper than Portland cement. A 3D printed sandstone structure is faster to build than one made of traditional building materials.

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The architects at Amsterdam-based Universe Architecture in front with the designer Janjaap Ruijssenaars have proposed a house that will be entirely 3D printed. The Landscape house might be the first 3D printed house in the world and will lay down the path for fully 3D printing at architectural scale. For the printing method, Enrico Dini’s D-Shape will be used. Instead of creating a flat strip of material and bending it into a shape like a Mobius strip, the gigantic D-Shape printer will make pieces of the 12,000-square-foot building, spitting out 6-by-9-meter section that will eventually be assembled into the full building.

The project could take about 18 months to complete, with the printer working for up to half a year while the estimated cost will be $5.3 million to build. Construction of the Landscape House is expected to begin in 2014.

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Protohouse was designed by theLondon architecture team Softkill Designa and it is a conceptual house that would be 3D printed in sections in a factory and fitted together on site. Designed to cantilever out from a hillside, the structure of the house was generated using an algorithm that imitates bone growth to deposit material where it is needed along lines of stress, resulting in a fibrous web rather than a solid envelope. The house would be printed in 31 sections using the largest 3D printer currently available, then transported by truck to the site and fitted together.

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While Dutch architect Janjaap Ruijssenaars from Universe Architecture in Amsterdam plans to print a one-piece "endless" building latest in year 2014, and Softkill Design, a London based design collective, is working on a second version of the 3D printed Protohouse, another Dutch studio, DUS Architects, is planning to build the first 3D-printed canal house in Amsterdam. It will be 3D-printed entirely. DUS Architects will work with KamerMaker, the world's first largescale movable 3D printer, or 3D printing pavilion. The design of each building component will be first 3D printd on a "small" 3D printer, at a scale of 1:20. When the design is optimal, the KamerMaker will then print out each room in one piece. The construction will start in the next six months. The printing procedure is directly visible to all people in Amsterdam, as a continuously growing exhibition. In the winter of 2013, the first floors and facades of the house will be finished.

Currently the printing material is polypropylene, but DUS Architects hopes in the near future to use recycled plastic as material.

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This structure, called Echoviren, is the first inhabitable architectural structure using standard 3D printers and it was constructed by California studio Smith&Allen in August 2013. It is a 10 x 10 x 8 foot pavilion which consists of 585 individually printed components produced on seven Series 1 desktop printers. It took the printers two months and 10,800 hours to print the components, but just four days to assemble them on site. The components, each measuring up to 10 x 10 inches, were snapped together to create a perforated structure resembling an igloo with an opening at the top. Each component is made of a plant-based PLA bio-plastic, meaning the structure will decompose over time, disappearing within 30-50 years.

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3D PRINTING IN REMOTE AREAS

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REASONS and ADVANTAGES Due to their embedded characteristics it is of no doubt that the 3D printing technology is optimum for use in remote areas. Most of these characteristics are represented by the essential idea that 3D printing has a substantially different approach to manufacturing as we know it and that everything is done in one job. Besides the general characteristics of the 3D printing(to which we can reference the 10 principles of 3D printing specified by Hod Lipson and Melba Kurman) there are factor dependent reasons why this technology is suitable for use in remote areas. On a synthesized approach, the reasons can be stated as follows: - automation of the printing process - the ability to self-operate without the need of a human operator and controller throughout the printing process. Given the conditions of some more extreme remote environments this could be an important advantage.

- creation of on-the-spot objects - the ability to replace broken or damaged parts or tools by printing new ones on the spot, thus avoiding long distanced, timely and costly transportation, especially if there is a weak or inexistent infrastructure. The rate of replacement is direct proportional to the degree of forces that act in that environment, degree of the object to stand to these forces and to the purpose of utilization of the object element.

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- minimum manipulation skill: untrained or less trained persons can learn the minimum operation procedure to print the required object. While is not really as simple as pressing a button, it is neither that far away from this idea.

- a 3D printer can print different objects each time which makes it suitable not only for printing the standard required objects for the remote environment, but depending on the situation which need self-adaptation to the environmental change, it can produce on-demand customized objects that will serve the new needs. That means, the same type of printer can be used in many remote environments, each one with very different characteristics and with their own survival requirements, to print very different on-demand customized objects that would fit these requirements. In some cases, like printing a water filter or/and a water container, this ability could be life saving.

- using the local materials such as sand/dust, clay, salt and water to create functional objects. For millennia local populations solved most of their needs by manufacturing their products with the materials found within their reach, usually an area not bigger than few square kilometers, whether that means earth, stone or wood. With 3D printing technology these basic materials can be not only simple used to fabricate new objects but to reorganize and combine them in new patterns.

- risk minimization: having a simple and small machine or many instances of the same type of printer that can produce different objects each time, will minimize the risk of intervention in case of defected systems or damage to the machine. A large traditional manufacturing machine, if it breaks, it will imply large reparation or replacement costs, while if a smaller 3D printer breaks, then it will imply lower costs or no costs at all since other printers can print the same object that the broken one was printing before, although this is not the case in the large specialized manufacturing machines. On top of this, the other printers can print(dependind on the materials available and printing performance) replacement parts of the broken printer or even self-replicate themselves.

- creating in advance the conditions required by the humans before they come to conduct their researches and perform their activities for whatever purpose they would have. This could mean that a research camp or temporary/permanent settlement can be implemented prior to the presence of humans in the area. The printers can be deployed on site from airplanes, just as on Mars the mars rovers are deployed from orbital space units.

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POTENTIALITIES The potential of using this technology in remote areas is huge and can be shadowed only by the more intelligent, adaptable and flexible robotic systems. While 3D printing can, in theory, be suitable for remote areas, at least for their purpose, we don’t have yet the experience of how to implement it in these areas especially if they are subjects to extreme conditions. However, when you combine the general features of 3D printing technology with more capable robotic systems that are designed specifically for remote areas and/or extreme environments, then you could say the potential is indeed huge. These more capable robotic systems can benefit of more adaptable features for self-sustainment and to resist the factors and forces of the environment they are in while their performance is verified through past experiences. Among these advanced robotic systems we can name the land and sea ROVs (Remotely Operated Vehicle), lunar module, UAVs (Unmanned Aerial Vehicle), drones, humanoid remote control vehicles or even artificial intelligent humanoid robots.

When these advanced robotic systems and 3d printing technology work unitary then you can achieve an optimum operating system that has the potential not only to survive and research its environment but to transform it as well.

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The potentialities can be subdivided in two classes, first one when a general 3D printer, that was not created for the specific purpose to operate in a remote environment, is introduced in this new environment with the purpose to create objects that are needed there, and the second class when the 3D printing technology is combined with advanced robotic systems in one single unit with multiple purposes of which 3D printing is one of them. The two classes have the following potentialities:

1) A general 3D printer that was not intended for the specific purpose to operate in a remote environments: - if it can work with the local materials then it can create as many objects as needed in limits of the energy available, of the additional substances required that are not to be directly found in this areas (like binding solutions) and usage resistance.

The type of objects created are also limited to the size of the printer, material use and printing performance, but the most common objects that the printer was intended to print anyway, independent of the location, they could be printed. They can be basic and simple objects like water containers, pots, bowls and bricks.

- if it can print only with specific materials, the limits are more, but the potential is that if it uses materials for high-quality and varied objects, then high-quality and varied tools can be created on-the-spot, which will solve the problem of replacement when they break. This is the case when laser sintering printers can create metal tools to replace the damaged ones. In space, maybe the most extreme environment, where you can not expect for a tool replacement very soon and cheap, this feature has a tremendous potential

2) A combined system of 3D printing with advanced robotics - if the system is not made for a specific remote area but for a general use in remote areas, then it can be integrated in that environment in the limits of its operability and material use to create on-the-spot objects. This robotic system can have access in different regions to collect the material needed and print objects on the same spot or elsewhere depending on the needs.

- if the system is made for a specific remote area, then it can optimize its applications to the environment of that area to create objects made of the local materials. It can create objects that are prior designed to use the local materials so that they will behave in the most efficient way based on the properties of the local material. On the moon, for example, a robotic system can be specific designed to 3D print with the local material that is the lunar regolith (the surface dust found on the moon) in low gravity and inexistent atmosphere conditions.

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STRESSFUL ENVIRONMENTS AND SELF-ADAPTATION A stressful environment is a an environment characterized by conditions that are improper to human survival. Many remote areas, either on Earth or outer space are considered as extreme environments in which general life forms can not survive without some extra protection. However evolution has made so that, in time, life found a way to adapt to these environments. These life forms are called extremophiles and they thrive in these environments by incorporating protection mechanisms and by adjusting their metabolism to the imposed conditions. Although many of these organisms are microbial life forms, there are also complex organisms that can face the conditions of an extreme environment. The first part in adapting to these environments is stress perception. In this way they can develop defense and repair mechanisms in response to these stresses for the primary need, that is the survival of the organism. Of an equally importance objective is the capacity to grow and reproduce under these extreme conditions. Among the most used mechanisms for survival in these environments is the avoidance strategy. This presumes that the organism will reduce its metabolism to a hibernation state, and will remain dormant in that state until the conditions are good for it to retake i’s normal functions. This is the case with desert perennials plants, that remain dormant during dry seasons and spring to life when water

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becomes available. Some organism are even capable of reducing their metabolism to a state of cryptobiosis in which the metabolism becomes undetectable and can remain in that state for years and even centuries. Other plants, like Xerophytes which include the family of cacti, have evolved so that to be capable of storing and conserving water, while having no or few leaves to reduce transpiration.

Microbial life is the most abundant life-form that exists in the more extreme environments because they have simple mechanisms that can cope more easily with the exchange of substances that are found in these environments. For example, a bacteria needs only water, energy and few building block to survive and it can extract its energy and material from the environment they are in through a simple procedure. But a complex organism needs more than that, as the more complicated life-forms are also more demanding in terms survival needs and activities to perform.

The mechanisms that organisms have evolved to adapt to these conditions are diverse, and depending on the stresses, different organisms have built more or less similar responses to cope with specific stresses. But different approaches to the same type of stress have also evolved, that shows us that there are multiple solution to the same problem.

One thing is for sure, that these organisms are shaped by the stresses they are subjected to and that the more extreme environmental stress have generated relatively fast changes in their genome to make them adaptable to these environments.

Critical views and considerations: - while designing a structure in an extreme environment, the structure should respond to the stresses that are found in that environment and should be envisioned by considering a construction approach starting from the very small particle that is made of and this very small particle can be the smallest material deposition or fusion that the printer can create.

- reorganization of matter at micro scale and combining different materials at this scale for an efficient manifestation could create an optimal adaptive system that is responsive to the environmental stresses. This can mean the creation of functionally graded materials (FGM) whose composition and structure vary across their volume thus creating different proprieties in different parts of the object.

- generating a responsive structure by reorganizing the matter for the purpose of creation of an optimal adaptive system presumes either an inhered knowledge about the optimal systems that can thrive in that environment or, similar to the process of evolution that is found in nature, an experimental bottom-up approach that will be based on a simulation of material behavior under specific conditions to generate the optimal patterns that a structure at different scales can be made of for that environment. Imagine that a sequence of computer simulations is made for the material behavior each one being considered as a generation built on top og the previous one, and with each new generation, the system will come into a more enhanced shape. This is also how bottom-up artificial intelligence is created.

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DESERT, OUTER SPACE, MOON, MARS AND BEYOND 71% of Earth’s surface is water. Of the remaining 29% land surface, 33% is dessert. The potential that the word deserts holds for us lies in the resources they hold, whether that is oil, natural gases, solar energy or wind energy. However, the harsh conditions that are representative of these deserts are a limitation factor for a human intervention in these remote areas.

Further away from Earth, the notion of remote area can not have a better significance as in outer space and on cosmic bodies such as Moon and Mars. These bodies can be considered as deserts as they are subject to extreme climatic factors and emptiness.

By using a combined system of 3D printing with advanced robotics, more accessible interventions in these areas can become viable. Thus, it is of no wonder why many of 3D printing proposal applications in architecture and not only are imagined in these remote areas. Currently proposed projects are considering the hot arabian desert, Lybia, jordan desert, Moon and Mars. In each case, the printer will use the local materials such as sand and regolith. The material can be sintered by using the sun power like in Solar Sinter in hot Earth’s desert, microwaves on Moon, or it can be solidified with a binding agent solution such as the magnesium oxide saline solution used by the D-Shape printer or the polypavement soil-solidifier solution used by the Stone Spray printer.

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Solar Sinter created pot

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German designer Markus Kayser has built a 3D-printing machine that uses sunlight and sand to make glass objects in the desert. Called The Solar Sinter, the device uses a large Fresnel lens to focus a beam of sunlight, creating temperatures between 1400 and 1600 degrees Celsius. This is hot enough to melt silica sand and build up glass shapes, layer by layer, inside a box of sand mounted under the lens. Solar-powered motors move the box on an x and y axis along a computer-controlled path and a new layer of sand is sprinkled on top after each pass of the light beam. Light sensors track the sun as it moves across the sky and the whole machine rotates on its base to ensure the lens is always producing the optimum level of heat.

Students Anna Kulik, Inder Shergill and Petr Novikov from Barcelona's Institute for Advanced Architecture of Catalonia have built a robotic 3D printer that creates architectural structures from sand or soil The Stone Spray robot sprays the grains of sand or soil out of one nozzle and glue out of another to make a mixture that solidifies as it hits a surface. Unlike other 3D printers, the robot's arm moves multi-directionally and can also print onto vertical surfaces.

A 3D printed model made during the AA Visiting School Jordan workshop in September 2013. The prototype is based on the desert morphologies characteristic to Jordan desert. “AAVS Jordan proposes rethinking the process of developing architectural interventions within the Jordanian desert. Set within the dynamic city of Amman, the rose-rock carved city of Petra and the echoing desert of Wadi Rum. Participants are encouraged to observe natural formation as a precedent for macro and micro architectural interventions within the desert ecology.

The unit theme is open to a wide range of scales bound to the participants research area of preference. However, the computational and physical systems developed must share the general agenda of the unit and be able to develop variation in response to architectural and contextual conditions.“ http://www.aavsjordan.com

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(As already mentioned in the architectural examples subchapter) - Ginger Krieg Dosier, an Assistant Professor of Architecture at the American University of Sharjah in the United Arab Emirates, has envisioned a new material to build transmission towers in the UAE desert, and it is based on the rapid growth of bacteria. She bases her idea off of the specific germ Sporosarcina Pastuerii, which is a common soil bacteria that can create a “biocement� material that has the ability to fuse with sand and, through a process known as Calcite Precipitation (MICP), creates a material that is sustainable, unlike wood, and unexpected, unlike concrete. The process is as such: the bacteria is grown and then fed into a 3-D printer, which will meld the bacteria with graded sand. This mixture is then molded into units, utilizing local industrial facilities to create the units with casts. This method of material creation yields little waste, and allows for accuracy throughout the building process, with units being created thicker or thinner depending on what each area of the tower needs.

FAB CLAY explores 3D printed architecture in clay. Material samples are made by hacking an industrial CNC Mill with a customized, arduino-controlled deposition head for paste-like materials.

Attached to an industrial robot, the head is used to print full-size architectural columns.

Developed Nasim Fashami, Sasa Jokic, Starski Naya Lara

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Architect Magnus Larsson’s proposal of a 6,000 kilometer-long inhabitable green sandstone wall along the saharan desert. The structure will be build with the help of bacillus pasteurii, a bacterial microorganism abundantly available in marshes and wetlands. The loose sand will be transformed into a fibrous porous structure that will sustainably control desertification while housing thousands of refugees. the crux of the project however lies in the natural microbial reaction of the bacteria with the sand particles that turn them into organic dunes of structurallysound sandstone,

Talin Hazber from American University of Sharjah has envisioned a design which is based on the idea that robots can spray a binder on the sand dunes and as the sand is blown away, the solidified part is revealed and remains in suspension. Those robots start to move and walk in the desert leaving behind traces which provide a temporary habitat for people to inhabit and as time passes, the settlements begin to erase themselves going back to their initial state.

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Cemil Ceyhan GONEN, Konstantinos PSOMAS, Sara Gemma SABATE GOMEZ, & Vishu BHOOSHAN

SyntaxERROR :The thesis proposes a development of a prototypical system based on tensioning and dynamic relaxation. The system is realized through a time based deployment of robotic agents. The research also explores the realm of material behaviour by testing deposition strategies and phase changing materials like resin and foam. The emphasis is to question the existing notion of element – node space frame structures by generating an in-situ agent based system for creating a shelter.

Created by Mei-Ling Lin, Shankara Subramaniam, Ling Han, Jiawei Song from AA School, the project has focused on a design-system using an innovative fabrication method for the construction of housing. Based on an on-site, layered manufacturing process using a paste-like material. Developed from the customisation of existing CNC technologies and incorporating CAD tools and scripting platforms, the research work was aimed at finding an equilibrium between materiality, design intent and fabrication processes.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

Tomas Rousek, Katarina Eriksson and Dr. Ondrej Doule are collaborating with NASA's Jet Propulsion Laboratory on plans for a modular architectural structure at the lunar south pole. Each module would be printed using a NASA robotic system, which would produce a ceramic-like material by microwave-sintering lunar soil, also known as regolith. There would be no need for glue, as the particles would naturally bond themselves together when heated to the right temperature by the robots.

Unlike rival proposals by Foster + Partners, which involve building layers of soil up around an inflatable frame, the Sinterlab concept is based on a system of rigid modules that can be pieced together to form a structure. The concept has been developed using a Microwave Sinterator Freeform Additive Construction System (MSFACS) and would be carried out by NASA's six-legged ATHLETE robot (pictured below). A prototype of the robot has been tested in the Arizona Desert for some of the processes it would use on the moon.

Foster + Partners‘ moon base is a landmark project for the field of 3D printing that could pave the way to lunar colonization in the future. Part of the lunar base could be transported by rocket in a tubular module that also serves as the protected entrance to the base. The tube entrance leads into an inflatable dome that serves as a support structure and defines the shape of the base. Inside, a 3D printer operated by a robot would print a protective shell of regolith layer by layer over the inflatable dome. The structure is being tested with simulated lunar soil at a smaller scale in a vacuum chamber, which is similar to the non-atmospheric lunar conditions. If the project is given a green light, the lunar accommodations will be based at the moon’s south pole, which receives non-stop daylight.

Along with Foster + Partners, the ESA is working with Italian space engineering firm Alta SpA, Monolite UK (for the 3D printer) and Scuola

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INQUIRY INTO NATURAL ROCK FORMATION

PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

EROSION VERSUS DEPOSITION The movement of rock pieces from one place to another, once they have been loosened by the action of physical or chemical weathering, is known as erosion. Small pieces of rocks, sediment, and even soil are moved away by the action of natural geological agents such as flowing water, blowing winds and melting ice of glaciers under the influence of gravity. Thus, in simplest of words, erosion is removal of loosened rock pieces from a higher elevation to a lowly point with the action of natural agents. The process of erosion is complete when the journey of all particles falling and flowing under gravity is done with and all the sedimentation gets deposited and settles on the surface. This is the process of deposition that is technically speaking a part of the process of erosion. If erosion can be thought of as a sequence, it includes detachment, entrainment, transport, and finally deposition. Detachment is end process of weathering that finally results in loosening of rock particles. Sand is the resultant of this erosion and sand dunes are the resultant of deposition.

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AGENTS OF TRANSFORMATION - the Honeycomb rock structure Weathering is the main reason for rock transformation. Rock weathering agents include Wind, running water, waves, sunlight, rainfall (precipitations), glacier, plant roots growth, burrowing activities of insects and animals. It gradually weakens rocks, and eventually produces new geological materials (rock fragments, sands, silts and clays) that are more stable in the new environment. Weathering generally produces finer and less dense rock materials, and weaker, more porous and permeable rock masses. Among the transformative weathering processes is the honeycomb weathering.

Honeycomb weathering(seen in the left images) occurs throughout the world, but the origin remains a matter of controversy. Wind erosion, exfoliation, frost shattering, and salt weathering have been proposed as explanations. Honeycombs kind of cavities result from disaggregation of mineral grains by evaporation of salt water splashing on the rock. This cavities can hold salt water and as long as sun reaches the water inside, the water evaporates and the cavities further enlarge. When the light can no longer reach the water inside, the process is stopped. It is believed that also algae living within the rock surface protect the walls separating the cavities (septa) from further evaporative erosion.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

DESERT CAVES A is a natural opening in the ground extending beyond the zone of light and large enough to permit the entry of man. Occurring in a wide variety of rock types and caused by widely differing geological processes, caves range in size from single small rooms to interconnecting passages many miles long. The agents of rock erosion in the dessert can create intricate morphologies of the terrain as is the case of Jordan desert where complex rock formations have occurred (see left images). The erosion of these formations is due to the wind and water and the chemical bounding of the material itself which is sandstone. In one aspect, sandstone is a very common stone and is more easily eroded than other types of stone. But the sedimentation process that created it in the first place is based on the idea that granular material can be compacted in a solidified one which is similar to what currently 3D printers in architecture like D-shape do.

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INQUIRY INTO BONE PATTERN FORMATION

PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

SELECTIVE MATERIAL DEPOSITION Bone is a unique natural material that can solve many structural problems generated by the mechanical stresses and applied loads on it. The solution lies in the selective material deposition approach, the ability to configure one or more materials into a structural geometry that will give to the bone element its characteristic strength while keeping a minimum ration of material/volume. This will allow the bone to perform in a most efficient way under heavy loads or stresses while keeping its body as light as possible. The bone material distribution acts as a FGM (functionally graded materials)in which each “layer� has its own function. The outer layer, periosteum, is uniform and continuous and allows for the cartilages of the muscles to bound on it. It follows then the compact bone, that is the main body of the bone, that evolves towards the central axis of the bone to a spongious structure also called the cancellous bone. This layer has the role to distribute the stresses from one side of the compact bone to the other while keeping the minimum material. It will reinforce or weaken by reconfiguration/alteration of its pattern or assimilation/loss of material mass.

Besides the material location distribution the bone has to ability to entangle different materials with different proprieties into one mass for a better performance. The solution consist of a matrix of collagen fibers, a protein which is strong in tension (collagen is the main component of skin and tendons) that creates a matrix which is then filled in with calcium salts, which are strong in compression, analogous to concrete.

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Differentiated densities of the calcium composites.

From outer layer that gives the shape of the bone to the inner layer that gives the mass/volume stress performance.

Cases in which the trabecular microstructure of the bone is differentiated by factors as mass and geometry

Http://courses.washington.edu/bonephys/phystrength.html

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

WOLFF’S LAW Was published by Julius Wolff in1892, as a study work on bone transformation mechanisms.

Wolff’s law states the behavior of a normal healthy bone structure will be dependent on the forces that acts on the bone. Thus, the mechanical stresses that the bone experiences will determine the bone to respond in a way so as to produce a minimal-weight structure that is adapte' to its applied stresses. This means there will be changes in the direction of the internal porous structure of the bone and depending on the loads and strains, an increase or decrease in its mass to reflect the amount of functional pressure. The functional pressure is the pressure to which the bone can respond in order to preserve its needed performance. The process under which this behavioral change can occur is called mechanotransduction, by which mechanical stresses are converted into biochemical signals in a cellular signaling interaction.

On Earth, we are subject the a force of 1G due to the Earth gravitation. From born our bones are still unsolidified and flexible but as we grow, our body mass grows and our bones respond to this load force by increasing their internal strength by ways of material assimilation in a selective deposition process. In low gravity environments, like in outer space, our skeleton is no longer subjected to gravitation stress and tends to loss mass.

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Stresses distribution

Responsive internal bone structure

Http://meddic.jp/Wolff_law

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

COMBINED TECHNOLOGIES: 3D PRINTING AND COMPUTATIONAL DESIGN Maybe the best reason for using 3D printing technology in any field is because of the rapid development of digital manufacturing, and in a specific sense, the computational design.

This is a promising technology for creating algorithm generated geometries, selfcustomizable for specific parameters. These parameters are controlled in entangled space, similar to which our universe works, which presumes that any change in one part of the system will have repercussion in all the other parts. Similar to the anthropic principle, the problem is to find the equilibrium between parts so that to create a functional harmonious system. While the system is totally controllable, the output is not always, at least visually, predetermined. Based on a form finding approach in response to external factors, such as DNA is the programming language for generating the optimal adaptable organism to its environment, so does the computational design is the tool of generating and manipulating geometries in real virtual space. One small change in one of its components will output different results each time. The advantage that the generated element can be controlled up to its microstructure simply by adjusting some of the input parameters. Then, these results can turn out to be a better solution than simply by thinking to the set of specified inputs. The question is not if this computational design technology will overcome the human creation ability, since it is, from my view, just a tool like any other, but a powerful one, at least and until recently, just in the screen display.

The power of computational design is huge but when you combine it with the 3D printing technology then we can really unleash its potential and materialize “our� visions.

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Www.michael-hansmeyer.com

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

TOPOLOGICAL OPTIMIZATION METHODS Topology optimization is a form finding technique which seeks to optimize a certain material distribution with given boundary conditions (ie. types of supports and loads). It departs from standard form finding techniques in that it assumes that a volume of virtual material can continuously vary its stiffness or density throughout space. In principle, the structure of an object will depend on the applied stresses so that when these stresses are applied on the object there are stress lines flowing through the object. These stress lines are of a critical importance for the integrity of the structure. All the other parts of the object are considered as redundant. The topology optimization method has a great advantage of finding the minimum material use and distribution, similar to bone formation, for the object o withstand the applied forces.

Among the topological optimization tools we can mention Topostruct and Milipede (a plug-in for Grasshopper) developed by Panagiotis Michalatos and Sawako Kaijima, and SolidThinking Inspire developed as part of the SolidThinking suite developed by Alex Mazzardo and Mario Mazzardo with Guido Quaroni.

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PROJECT PROPOSAL SAHARA DESERT

PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

LESSONS LEARNED

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1 - 3D printing is an almost fully automated process which enables it to be used in remote areas 2 - 3D printing can create on-site custom made objects that is very useful for application in remote areas where there are no available tools.

3 - 3D printing can use the local materials and current 3D printers for architecture best work with sand, thus a printing application can occur in sand deserts 4 - 3D printing can be best used for architectural purpose in remote areas to create shelter structures 5 - 3D printing can create complex geometries that respond to internal and external factors such as load bearing stresses found in architecture and organize the material for optimum efficiency in relation to mass/volume (as in the bone pattern formation) which is critical in architecture application. This can be done by topological optimization methods.

6 - an omnidirectional 3D printing process can be used to create larger objects than the printer’s body which is suitable for large scale object designs 7 - an omnidirectional 3D printing process can create a larger diversity of objects including with horizontal surfaces and can add and extend new parts in different points of the structure 8 - the main characteristics of a desert is its remoteness and extreme climate conditions which will require an adaptable structure to these conditions 9 - one of the interesting natural rock formation in the desert are the desert caves which can act as an inspiration source for a shelter structure in the desert

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

PROJECT’S GOAL

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Considering the fact that 1/3 of land surface is desert and that the desert is a remote area, hardly accessible by humans, yet holding a lot of potential, my project will focus on the particular aspect of intervention within these extended remote areas. Among the Earth’s hot deserts, the largest one is Sahara, and within Sahara desert the most extended remote area is The Grand Oriental Erg located in the north central part of Africa with no permanent human settlement within a radius of 200 km.

The project goal is to make an architectural intervention within this remote area, by implementing diffused located human shelters that will act as intermediary and temporary human habitation points in this area between more significant human settlements. In time, as more people will inhabit the place, and water problem will be solved, extensions to the structure will be added and a more permanent settlement can be achieved.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

SITE Location: Sahara desert - Grand Oriental Erg - sand dunes - hot/cold fluctuations - wind, sand storm - open field, no shadow - water scarcity - lack of other resources agriculture - food - emptiness, no civilization Project - developing an inhabitable structure in the desert Why - to provide intermediary human settlements points between long distanced cities in remote areas of the desert

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TRIPOLI

OURAGLA 43 7

38

km

7

km

Grand Oriental Erg GHADAMES

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

WIND FREQUENCY - AVERAGE YEARLY

AVERAGE WIND TEMPERATURES - AVERAGE YEARLY

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WIND FREQUENCY - SUMMER

WIND FREQUENCY - WINTER

AVERAGE WIND TEMPERATURES - SUMMER

AVERAGE WIND TEMPERATURES - WINTER

MAXIMUM WIND TEMPERATURES MIDDAY - YEARLY

MINIMUM WIND TEMPERATURES NIGHT - YEARLY

CLIMATE Climate: TRIPOLI, Libya Latitude: 32.7째 Longitude: 13.1째 (+2 hr.)

AVERAGE RELATIVE HUMIDITY - YEARLY

SUN PATH DIAGRAM

AVERAGE RAINFALL - YEARLY

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

SCENARIO

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A set of 3D printer robots will be deployed in this remote area to construct the structure of the shelter. At first they will be controlled by humans who will make the preliminary programming of the machines and connect them to a digital system through which the machines can be controlled in real time from the distance through satellites, similar to Mars rovers. When the preliminary preparation is done, the printers will operate entirely unattended by any human presence and will start building a relatively preprogramed structure while also making real time adjustments based on the conditions met. The decision making will still belong to humans as they will remote control the printers but the incorporated physical systems will still need timely readjustments and refilling the binding solution tanks by on site human-controlers. The structure will be build entirely with the local sand which will be solidified with the binding solution.

Intermediary intervention equipment will also be deployed on-site before the construction process while other equipment will be located within the closest human settlements. As the structure will take shape, passers through the desert can start to inhabit it. The printers will incorporate as well satellite communication between these passers and constructors with language detection and conversion systems.

The created structure can then be extended, if needed, to form a more relevant human settlement in these remote areas. If it will not be used for extended periods of time, the structure will erode by natural processes and be assimilated in the desert.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

MATERIALS CONSIDERATION The materials to be used for the structure are desert sand and binder.

The sand is an abundant granular material and it can find many architectural applications because of its abundance. Within the Grand Oriental Erg it covers its entire area, thus in principle, the construction site can be located anywhere across it. The most common constituent of sand, in inland continental settings and non-tropical coastal settings, is silica (silicon dioxide, or SiO2), usually in the form of quartz, which, because of its chemical inertness and considerable hardness, is the most common mineral resistant to weathering.

In terms of particle size, sand particles range in diameter from 0.0625 mm (or 1â „16 mm) to 2 mm. This allows it to be carried by the wind and deposit into sand dunes representative of many deserts including Sahara.

The question is how to bind it together into a compact element. From the previous research of printing with sand we have identified several methods for this problem among which there is the saline magnesium based solution used by D-Shape, microwaves used by lunar printer and solar rays used by SolarSinter.

The binder to be used for this particular structure is polypavement, which is the same binding agent used in the Stone Spray Project where they sprayed the sand and glue concomitantly to form a solidified structure.

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Polypavement is a liquid soil solidifier that can work with different natural materials including sand..While its intended purpose was to use it for creating natural asphalts as an alternative to the artificial ones, the solidified earth proved to be even harder than the traditional asphalt. Its advantages is that it is easy to get in any amount, has a fast drying time and structural strength, works well with sand and produce no waste.

Sand particles as unbounded

Sand particles bounded in a solidified structure by polypavement.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

REQUIREMENTS AND GENERAL STRATEGY What?

- the structure will need to accommodate travelers through the desert - must deal with high temperature variations, solar radiation and sand storms - must allow for future additions, a structure that grows in time, as the people will use it more often and establish there on a permanent basis (something like the development of a small city) in which case must provide the necessary resources for a long term inhabitation or even permanent - must be accessible and visible from long range distances

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How? - by using a 3D printing technology to print with local materials (sand) in order to create the structural frame onto which different purpose oriented components will be added (if necessary) - incorporating solar technologies as primary mean for the operation of the printers and running the facility - incorporating other technologies for the production of the necessary resources (depending on the inhabitability period of the settlement)

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

ADVANTAGES AND DISADVANTAGES OF 3D PRINTING WITH SAND IN THE DESERT Advantages: - reduction in time and cost of transporting and maneuvering high quantity materials and components from far distances - sustainability by using the local materials and integration in the surroundings - automation of the printing process (no need for extensive human intervention) up to the point of “lights out manufacturing� level. As the desert conditions are quite harsh, the automation of the printing process is essential in this case - solving the stresses distribution with less material by printing complex structural patterns, when the used material is not strong enough, although this is subject to its limits.

- creating needed tools and objects when you can not acquire them locally, which makes it also an essential one.

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Disadvantages: - sand in combination with a binder can turn into a sandstone. However, sandstone is not a very structural optimum material. While it has similar properties with concrete, unless it incorporates reinforcements, it is limited in its structural performance, and integrating other materials or components in the printing process for structural stability, is not yet a very developed technique - harsh conditions of the desert that can compromise the systems - access and mobility problems (how can the printers be assembled or moved around the place)

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

THE 3D PRINTING TECHNOLOGY TO BE USED - CONSIDERATIONS - the load bearing performance in specific points of the structure depends also on the layering direction of the printing. The current best printing techniques are the horizontal layering ones, thus their disadvantage if the structure has different stresses orientation.

Considering that my structure has to withstand not only gravity but also wind/sand storms and sand pressure (accumulated sand around the structure), a multi directional printing technique may be more efficient - at the same time, a multi directional printing process can allow for future additions, extensions and connections, independent of the place to be printed. Future extensions will depend on the human population growth over time and resources productivity development in that settlement. It may take the shape of a unitary large structure or separated smaller habitable units connected by an infrastructure - due to the harsh conditions of the desert, the robots/printers must self maintain themselves besides only printing (especially if the humans will not be around during the construction process). In time, as they will inhabit the place, they can have more control over the printers to extend their settlement in their desired way.

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- secondary purpose printers (more technologically enhanced) will be used to create and replace the parts of the main printers, where the majority of the material used will be recycled from the main broken/old printers - as more settlements will arise across the desert, this will allow for a better information and good exchange that will increase their prosperity. New technologies from the developed word can be easier implemented in the desert and work towards increasing resources provision - the 3D printing technology will have as main purpose to create the structure of these settlements

- the design feedback could be fed directly into the printer, not from a computer simulation, but from reality. Imagine a 3D printer that would know what it needs to print and adapts to the conditions of the print. Most 3D printers are “blind” in that they execute their instructions and don’t look to see if the instructions yielded the target object. Such systems are called open loop. On the other hand, a closed loop printer is one that “watches” the outcome of its printing and adjusts dynamically in response to various situations. Closed loop printing contributes more than just monitoring the shape of printed output. A closed loop 3D printer, if programmed correctly and given the appropriate hardware to convey environmental feedback, could monitor the strength of material it is printing and add material if Necessary.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

THE 3D PRINTING TECHNOLOGY TO BE USED - SPECIFIC DETAILS - it will act not as a one fixed printer, but as a swarm of interactive robots(size: yet to be determined). This will allow for an enhanced flexibility in the construction process, by locally defining the necessities, economizing energy and time. As previously specified above, they will build in a multidirectional orientation adding new parts or establishing new connections between different parts whenever this would be required. The primary material used, sand and binder, will have to harden instantaneously as the structure will be printed, thus eliminating the need for formworks, as well of reducing the time of construction. Important structural parts will be printed before adding the secondary importance ones (in horizontal layering all these parts are printed concomitantly from bottom up, which is sometimes a disadvantage if there is no extra temporary support; take for example an arch bridge). When the extra temporary supports are needed, they will be printed first, with the possibility of removal at the end of the process - small robots printers are also more easily deployed in remote areas, easier to assemble, to be fixed or replaced, recycled or dismissed - they will use solar energy by incorporating solar cells or sun tracking panels on their body (like the Mars rovers) with a battery storage option

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- if one breaks, the other will continue to operate. The malfunctioning one will be removed by a replacement. Meantime, a secondary purpose printer will print new parts of the broken one that can become again operative - they will work in synchronicity and always communicate as a network. When two separate parts started by two different printers have to be merged, one of the printers will switch to another instruction, while the other will do the merging and finish the job. After finishing the job, it will relocate itself to build another part, by scanning its surrounding and constantly referencing the preprogrammed shape stated in their software. If there are no new parts needed to be started it will assist the other printers in the printing process of the unfinished parts until these parts will be finished as well. Although this requires high artificial intelligence synchronization (reference to an ant colony building process), its worth mentioning that this kind of A.I. exists today, and due to the exponential growth in this field, major performance increase in robot synchronization may be achieved in few years - they will attach to the structure in any position and will print the material through a multidirectional arm, placing it over a section area.

The sand and binder will be combined inside the printer and will harden as it will exit the arm. As the part is being built, the robot will advance on it to further complete it - the material provision is made through a set of tubes, at least one for sand and one for binder were both materials will be absorbed from the ground by using a dredging technique very similar to the one used in Palm Jumeirah peninsula. In order to avoid knotting situations and extra bearing weight, the tubes will be temporary fixed on the structure by the printers themselves and removed as the printers will climb down on the structure - after the primary structure will be finished, 3D printed solar graphene sheets will be added by robots on specific areas of the structure to capture solar energy and convert it into electrical energy. It's important to mention that graphene/carbon nanotubes can be modeled on any shape and can as well act as an electricity transmission system. Research on this technology is currently underway - transparent surfaces will be made of the sand quartz

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WATER PROBLEM - water will be pumped or transported from the nearby seas, and desalinized by using the graphene filtration properties (the graphene is the best known water filter in the world as it allows only water to pass through). This means that the same water disposal can be recycled numerous times, thus eliminating the cost of producing/transporting additional water. It is a fact that water evaporates at faster rates in the desert, thus a reversing cycle technology to produce fresh water from evaporated one is also possible and maybe much cheaper. At the same time the air humidity varies across different places. In Sahara, for example, the air humidity is approximately 20%, but with a sufficient efficient technology of capturing water from the air is possible to provide some extra water. These technologies already exist today, and by making a combination of them, the water problem can be solved, not to mention the underground water that can be reached as well.

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EXPERIMENTATION In order to get the final shape of the project proposal a set of experiments were being conducted in respect to the statement that the bone pattern formation is the optimum methodology to be considered in this case. The reason for this, is because the local material, which is sand, although can be solidified by a binding solution, its strength performance still remains weak in comparison with other construction materials or composite materials. The solution to this problem lies rather in the selective material deposition ability of the 3D printing technology itself. The technology can create very complex and intricate shapes, but besides the esthetical reason, which is secondary in this case, the main advantage is that this ability to create complex shapes can solve the stresses distribution within the structure.

As we have learned from the previous research, the bone pattern formation stated by Wolff’s law is dependent on the applied stresses on the structure, so that the internal structure of the bone will readjust in such a way that will withstand these stresses while using the minimum material per volume.

The following experiments are based on this principle of bone pattern formation, where different internal structural organizations and material densities are considered.

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In this experiment different densities are being considered in a wall section based on the material density transition in a bone section where the outer layer, the periosteum, is the continuous and most dense one and the center of the bone is the most porous one.

The connections between the two parts of the wall can be more or less dense depending on the required strength performance but the material can be considered as a functionally graded material (FGM) where the degree of density will vary in different parts of the object.

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Here I tried to explore a fibrous system that is based on the antigravity system described in the research part. In principle the object is made by extruding these filaments following the stress lines of a digital model. The filaments represent the structure of an object onto which a mixed composition of sand and glue is sprayed in order to create the body of the object. The material of which the filaments are made of is thin granular sand combined with glass fibers. The glass fibers are extruded together with the sand for a tensile and compressive reinforcement resulted from the combination of the two materials.

In this case, the main inspiration was the Wolff’s law, as the structure pattern is differentiated along its cross section. More specifically I consider that I have omnidirectional stresses in the right part of the structure and horizontal stresses in the left part of the structure, thus the bone like pattern will always follow the direction of the stresses. The transition between the two parts was what interested me as to keep the structure differentiated yet uniformly intact. The created enclaves are imagined as possible spaces for sand deposition for filling in and reinforce the structure in a natural process of sand deposition.

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Having experimenting with topological optimization tools such as Topostruct and SolidThinking Inspire (described in the research part), I came out with interesting results that were unexpected in the first place. In the above case, I used Topostruct to generate stress based object morphologies. Three loads (seen in red) and two supports (seen in blue) were applied in a 3D space (a box) and based on the forces specified, it generated stress curves (seen in white). Then, the stress curves were used to generate a mesh around them that would be similar to the bone pattern formation in Wolff’s law. In the below experiment, which was conducted in Inspire, I tried to apply three supports (red cones) and four forces, one on top and three at the bottom (red down arrows) to a design space defined by five boxes.

The result was a structure whose material density was optimized for the specific forces and supports so as to keep a minimum material/volume ratio for the same performance.

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Here I tried to construct three series of more complex design spaces (the red boxes) and apply more forces and supports to each series. The result, as it can be seen is significantly more complex in each case, in order to respond to the changes in the stress lines due to the locations of the applied forces.

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In this case, I tried to generate a sample that is similar to the bone structure.

The sample is made of different sizes of sand particles to see how can they be integrated into such a shape.

Different thicknesses of the mesh were considered as well and different angles of view shows the overall continuity of the pattern formation. The end result looks very promising in terms of reorganizing the sand in a bone like structure that can be build in the desert by a process of 3D printing.

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UNIT SHELTER In order to create inhabitable spaces for the people and their animals a unit shelter has been conceived with the minimum requirements for survival. The main role of the unit will be to cast shadow in a place where the solar radiation is one of the biggest surviving problems.

Light radiation and heat radiation from the sun will make the evaporation process faster and giving the lack of water resources in the desert, it is of no doubt that this climate condition will create an accelerated body deshidratation. At the same time, desert surface temperature is higher than the air temperature and being in contact with the sand will further heaten your body.

The unit will be deep enough to create permanent shadow while also maintaining an open access to the indirect light. The midday sun ( when the radiation is at its highest point) is high above the horizon in this region to an almost perpendicular angle on the Earth’s surface and the shadows will always be projected within this angle. The minimum dimensions of the unit are based on the human dimensions while alternative dimensions can be considered for their animals and goods they carry with them.

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7.7 m

5.6 m

+2.5 m

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SOLUTION The unit shelter is considered as the primary element that can be organized in a superstructure made of multiple units. Inspired by the systematic swarm construction methods found in nature such as bee honeycomb construction and ant superstructure of earth galleries, this superstructure will be build on the same highest volume/area principle.

Considering also the cilmate conditions, a compact shape will always best respond to heat, wind and solar radiation. At the same time this aggregated form is shaped also by the direction of the prevailing winds which are more frequent during the summer from North-East direction, thus its’ openings will face the opposite direction and the winds. But the particular reason of building a compact agregated form in the desert is due to the characteristic of the sand which is a dynamic material. It is a granular material made of particles small enough to be blown by the wind. The sand dunes will always move in time and overtake any low structure in the desert, unless this structure will be regularly maintained. As my structure purpose is to act as a temporary shelter for people passing through the desert, it will be maintained in the limit of the time the people will inhabit it. Thus, it is expected, in this sand dunes landscape that sand mass will accumulate at the base of the structure partially covering it. Giving the essential requirement for the structure to be visible from far distance for people looking for a shelter the solution to build not only horizontally but as well vertically might seem more reasonable.

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BEFORE OPTIMIZATION

Following the experimentations with the bone pattern formation and topological optimization methods, the final assemble of units was optimized in one aggregated superstructure that forms connections, holes, cavities, bridges and pillars, all of them interconnected in a “homogeneous” yet porous system similar to the bone internal structure, for an enhanced strength of the superstructure. In this way I achieved both living spaces, represented by the units, as well strength generated through the entangled way these units connect in one system. Based on Wolff’s law, the connections and thicknesses in different parts of the superstructure are dependent on the direction and value of stresses. In respect to the topological optimization methods the strength of the superstructure is given by a minimum material/volume ratio without altering its performance. However the number of units that can be added and places to be added will dictate the final resultant shape and thickness of the superstructure.

AFTER OPTIMIZATION

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9.3 m +6.2 m

0.3 m

+2.5 m

0.00 m

+12.4 m

+4.7 m

30 m

141

20 m

+1.0 m

+2.5 m

+4.0 m

+5.5 m

+7.0 m

+8.5 m

+9.0 m

+10.5 m

+12.0 m

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

ROBOT 3D PRINTER

PRINTING HEAD

KUKA ROBOTIC ARM

OUTPUT PIPES FOR SAND AND BINDER

PHOTOVOLTAIC PANEL (total: 2) ROTATION JOINT IN X-Y-Z JOINTS ROTATION DISC PRINTER’S MAIN BODY (absorption and control system) LEG (total: 6) INPUT PIPES FOR SAND AND BINDER

FOOT (total: 6)

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200 cm

1 00

cm

100

87 cm

130 cm

70 cm

190 cm

cm

The main body rotates around the Z axis

The joints rotate around the X axis (with reference to the arms and legs position)

The solar panels and leg’s feet rotate around X-Y-Z axis

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

IMPLEMENTATION

As already described in the specific considerations subchapter, the 3D printers will act as a swarm of interactive robots highly flexible, energy self-sufficient by incorporating solar panels, fully automated, and highly synchronized. They will print in an omnidirectional process with the possibility to intervine on already finished parts in order to add extensions to the structure.

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

VISION

“I'm of the opinion that science fiction writers suck at predicting the future. We mostly go around describing the present in futuristic clothes.�

Cory Doctorow (science fiction author)

PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

THE FUTURE OF 3D PRINTING Since the future is very relative and every opinion on the future is very subjective, in the following I will expose some opinions about the future of 3D printing that belongs to people involved in this industry and research field and I will end with my own personal considerations.

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“In the future, buildings may be constructed by swarms of tiny robots that use a combination of printing and weaving techniques”, Oxman says. "I would argue that 3D printing is more than anything an approach for organising material," she says, using the terms "4D printing", "swarm construction" and "CNC weaving" to describe the future of architectural technology. "Today's material limitations can be overcome by printing with responsive materials," she says. "Gantry limitations can be overcome by printing with multiple interactive robot-printers. And process limitations can be overcome by moving from layering to weaving in 3D space, using a robotic arm."

According to this vision, the construction site of the future will owe more to tiny creatures like silkworms than to ever-larger 3D printers of the type we use today. "Transcending the scale limitation by using larger gantries can only offer so much," says Oxman. "But if we consider swarm construction, we are truly pushing building technology into the 21st century.”

Neri Oxman

“... we will gain the ability to program materials to function in desired ways. We will move from printing passive parts and materials to printing integrated, active systems that can sense and react, compute and behave. We will move from controlling an object’s mechanical functionality to controlling how it processes information and energy as well. When this day comes, we’ll be able to print (almost) anything—from a cell phone to a robot that strolls out of the printer. But like any sci-fi story, there’s also a catch. That robot will not look at all like today’s robots because it will not be limited by the constraints imposed by conventional manufacturing. Nor will it be designed directly by humans, because the new design space is too large for humans to fathom. The ability to manufacture active systems made up of both passive and active substructures with such freedom will open the door to a new space of designs and a new paradigm of engineering, one as powerful as biology... ...The next revolution after 3D printing will be the transition from analog to digital materials. Imagine a future where human-made artifacts are composed of billions of tiny building blocks. These building blocks each have the same size and shape, and the same electric and mechanical connectors. Like tiny LEGO bricks, no larger than 100 microns in size—the size of a pixel on your screen—they interlock. Each of the two dozen or so building block types is made separately in bulk, and shipped as powder in a cartridge for an assembler...

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PRINTING THESIS PROJECT BY MIHAI DRAGOS POTRA

...Technological singularity, a concept popularized by writer Ray Kurzweil, is a hypothetical future in which machines possess capabilities that enable them to accelerate their own development exponentially. One of the more widely recognized aspects of the idea of singularity is an “intelligence explosion” where intelligent machines design successive generations of increasingly powerful, even more intelligent machines. As sophisticated as modern-day manufacturing machines have become, they do not have the capability to design and produce more physical instances of themselves. Today’s manufacturing machines can’t redesign themselves in response to some sort of challenge in their physical environment. 3D printing technologies will challenge our notions of what’s normal, natural, or original by supplying a missing link in the speculation of singularity. 3D printers will someday fabricate active, digital matter that has the capability to reconfigure itself into intelligent machines that, in turn, will redesign and fabricate improved versions of themselves. The idea of machines making machines is a recurring theme in both science fiction stories and serious academic studies. There are probably two reasons for this fascination: One is a practical view of scalability. Creating a machine that can create more machines leverages technology to its maximum capacity: With no humans in the loop, production is limited only by availability of material, power, and time.”

Hod Lipson and Melba Kurman ”Fabricated: The New World of 3D Printing”,

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My own personal opinion: When we think about the future of a technology we can not omit the future of all the other technologies or the potentiality of new technologies that can appear in the future. We always try to imagine future things through the prism of our past experience and most of the times we were wrong. Who could have predicted the major impact the internet had on our lives, or on the opposite pole, the thing that we are still not going to our job in a flying car as in the animated cartoons “The Jetsons” or that we haven’t sent yet a human mission to Mars, not to mention Jupiter, like in the “2001 - A space odissey” movie. Thus, 3D printing as we understand it today may be very different tomorrow. Then again, is not only about this particular technology as a separate function but about a combination of multiple technologies into one. Data sensing, scanning sensors, responsive systems, digital simulation and computational design, robotic synchronization (drone systems), nanotechnology, superconductivity, bioengineering, etc are all technologies that will shape our world by ways in which its future still remains unpredictable, but when you combine these technologies, as Hod Lipson said, into a system of systems, then you can imagine the huge potential they will have. 3D printing is going to create a big part of our world but that remains in the degree of combining it with other technologies.

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BIBLIOGRAPHY

Books and reports: Hod Lipson and Melba Kurman - “Fabricated: The New World of 3D Printing” Chris Anderson - “Makers: The New Industrial Revolution” McKinsey Global Institute - “Disruptive technologies: Advances that will transform life, business, and the global economy” CAREX (Coordination Action for Research on Life in Extreme Environments) - “Roadmap for research on life in extreme environments” Anna Kulik, Inder Shergill and Petr Novikov - “Stone Spray”

Articles and websites: Http://3dprintingindustry.com Http://www.3dprinter.net Www.3ders.org Http://www.aavsjordan.com Http://www.dezeen.com/2012/10/23/protohouse-by-softkill-design/ www.dezeen.com/2013/05/21/3d-printing-architecture-print-shift/ Http://www.d-shape.com http://thecreatorsproject.vice.com/blog/dutch-firm-to-create-3d-printed-house Http://www.magnuslarsson.com Http://www.makepartsfast.com Http://bulletin.geoscienceworld.org/content/93/2/108 Http://www.fosterandpartners.com/news/foster-+-partners-works-with-european-space-agency-to-3d-print-structures-on-the-moon/ Http://www.treehugger.com/green-architecture/3d-printed-buildings-proposed-moon.html

THANK YOU NOTE The process by which I managed to build this thesis was not an easy one since the 3D printing technology is relatively new and not yet as popular as other more mature technologies and by further narrowing the circle to architecture applications of which there is still not a single significant real one, and trying to propose a new strategy and project has been quite a big task. However I was not alone on this path. In a most respectful way I would like to thank to my supervisor professor Ingrid Paoletti for showing a big interest in the subject I chose and her good advices, and in a very special and grateful way to architect Roberto Naboni that followed my work constantly throughout its tiniest details and giving me constructive criticism whenever there was needed.

Ce qui embellit le dĂŠsert, dit le petit prince, c'est qu'il cache un puits quelque part...

"What makes the desert beautiful," says the little prince, "is that somewhere it hides a well."

ANTOINE DE SAINT-EXUPÉRY, The Little Prince