INTRODUCTION
A. CRAFT: Value Contextualisation
While understanding the constraints and opportunities of this digital fabrication (RWC), it is interesting to see how the three key aspects of material efficiency, production accuracy and geometric customisation relate to Kenneth Frampton’s theoretical idea of ‘poetic construction’9, through the attention of proper ties of materials, the craft of making and structural logics.
These three aspects are studied within this thesis through the lens of value assessment. It delves into the definition of ‘value proposition’ by ‘adopting’ vernacular construction & ‘adapting’ it through technology.
Can this collaborative model of vernacular construction updated with current scientific knowledge be an alternative form of craft-integrated constructs? Can this approach address the UN17 SDG – United Nations Sustainable Development Goals for the Built Environment10 – to find ways and means to make human settlements inclusive, safe, resilient, and sustainable?
Parallel contemporary examples of these collaborative models in low-tech economies (Figure 06), illus trate how tacit principles have been effective in tackling these challenges through community participa tion and collective knowledge.11
Earthen buildings in Africa by BC Architects12 focus on ‘contemporary vernacular’ - constructing globalised architectural forms with local materials, craftsmanship and adapting traditional construction principles. These are examples of inclusive and sustainable settlements. Similarly, the post-rehabilitation redevelop ment of Gandhi nu Gam at Ludiya13 and the development of Vavaniya village in Rajkot, India 14 entails an instance of safe and resilient construction.
This model focuses on incremental housing customisation through core units and part kits, rather than ‘one house fits all’ solution. Learning from these economic models, this project seeks value assessment by contextualising this system of RWC within the rural craft-integrated constructs.
fig 07. Tectonic and cultural studies of the Bhungas, the traditional constructs of seismic region of Kutch, rural India.
This low-tech economic context is rich in its regional resources, namely, the availability of local clay for construction, tacit knowledge in the use of low-inertia lightweight materials, traditional structural knowl edge in form design based on force resistance and the presence of labour skilled in local crafts.
fig 06. ‘Contemporary architects’
for prototyping using local materials and
adobe wall (right).
skills from craftsmen. Here, Workshop at BC Materials making objects in rammed earth (left) and
The most significant of all, being the seismic resistant structural systems (Figure 07) – the circular global geometry of the Bhungas whose inertia forces are resisted through shell action providing excellent resis tance to lateral forces, low walls for stability and, thick walls as thermal walls and high plane stiffness.15 Tapping on these resources and learning from the seismic resistant local Bhunga forms, the context de mands structures16 that can be produced quickly for emergency rehabilitation, which can be assembled with ease and speed using low-tech available resources, constructed without any scaffolds, and can be locally produced at a faster rate.
9. Kenneth Frampton et al, Studies in Tectonic Culture the Poetics of Construction in Nineteenth and Twentieth Century Architecture. Cambridge, Mass: The MIT Press, 1996.
10. “Goal 11 | Department of Economic and Social Affairs.”, UNSDG, Accessed September 29, 2022. https://sdgs.un.org/goals/goal11.
11. Priya Shah. “Ludiya: Partnering with People an Effort in Redevelopment with Community Participation.” Community Redevelopment | Ludiya. Accessed September 30, 2022. https://www.priyashah.com/mig/ludiya.htm.
Ken De Cooman. “Down to Earth: Earth Building in Europe and Africa by BC Architect.” Architectural Review, July 12, 2021.
Priya Shah. “Ludiya: Partnering with People an Effort in Redevelopment with Community Participation.” Community Redevelopment | Ludiya. Accessed September 30, 2022. https://www.priyashah.com/mig/ludiya.htm.
Vishwanath Kashikar. 2006. “Tradition and Transformation: A Post Disaster Perspective on the Making of a Vernacular Place Design Assessment of Affordable Housing Projects View Project.” https://www.researchgate.net/publication/275964688.
12.
https://www.architectural-review.com/essays/degrowth/down-to-earth-earth-building-in-europe-and-africa-by13.
14.
0910
workshops
tacit
craftsmen plastering
The above mentioned contextual needs call for structures with interlocking components without mortar, like the production of modular geometries for self-supporting vaults without mechanical connectors in the Interlocking Shell Research at the Texas A&M University17 (Figure 08a).
These have two-fold advantages, one, the above-mentioned strategies as tested in the research and sec ond, that the mortarless self-supporting structures are seismic resilient as it allows a degree of relative movement to dissipate vibrations, prevents cracks and makes the overall structure less stiff than one with conventional mortar for longer sustenance.18 However, for optimum seismic resistance, these interlocking systems need structural coherence and must constrain kinematically relatively to one another, or topo logically interlocked.
This structural efficiency makes the individual construction modules and its’ interfaces, the key elements of the system and therefore, for accurate alignment and equal load distribution, the module geometry must be fabricated with precise cuts and least tolerances. Another need for these specifications is the rationalised discretisation of the modules.
It is an adaptable assembly with customisable set of modules, where-in each set is differentiated depend ing on their location and contribution to the overall structural performance. In other words, the set of modules have micro-variations compared to one another based on their topological behaviour and load bearing capacity. Thus the need for stereotomic modules (Figure 09b)
fig 08a (left top, bottom). Examining the structural perfor mance of the interlocking joints by FEM analysis software.
fig 08b (left top, bottom). Conceptual develop ment of topological interlockin from tetahedrons.
The individual modules must resist high bending forces and tension, and have force-interlocked interfac es, so that no module can be disassembled because of its kinematic hold to its adjacent modules. These topologically interlocking modules (Figure 08b) are therefore structurally performative in terms of their fracture resistance and controlled load transfer due to the articulated interfaces.
Thus, in these topologically interlocked self-supporting assemblies, the structural integrity lies both, in the geometry and location of the modules (inherent vernacular construction principles), and in the transfer of forces at their interface (scientific technical studies).
fig 09a (top left). Abeille’s flat vault, classical stereotomy
fig 09b (bottom left). Iterations of topological interlocking
fig 09c (right). Adaptation of the flat vault into a cer emonial arch and its stereotomic production process.
Stereotomy, as mentioned initially, is basically an art of cutting masonry forms and rules to structurally assemble them. In ‘classical stereotomy’, the assembly of the clear-cut interlocking stone modules defined the global geometry of flat vault, as established by engineers Joseph Abeille and Father Sebastien Truchet19 (Figure 09a).Later, the cut surfaces were modified to convex or concave cuts to adapt the ‘Abeille’ vault into grand arches or oblique vaults (Figure 09c).
This complexifies the calculation of the angles between the surfaces. Moreover, these complex stereoto mic joints also justify structural efficiency as studies show that non-planar three-dimensional joints coun teract vertical compression, torsion, and shear forces.20
15. Dr Krupesh Chauhan. “Study of Climate Responsive Building Form for Kutch Region.” GRD Journals, January 1, 2019. https://www.academia.edu/38889525/Study_of_Climate_Responsive_Building_form_for_Kutch_Region.
16. Monika Gupta. “Climate Responsive Vernacular Architecture of Kutch.” Academia.edu, April 4, 2018. https://www.academia.edu/36333761/Climate_Responsive_Vernacular_Architecture_of_Kutch.
17. Alireza Borhani et al. “Interlocking Shell Transforming a Block of Material into a Self-Standing Structure with No Waste.” http://papers.cumincad.org/data/works/att/acadia20_226p.pdf
18. Arcady V. Dyskin et al. “Mortarless Structures Based on Topological Interlocking - Frontiers of Structural and Civil Engineering.” SpringerLink. SP Higher Education Press, May 23, 2012. https://link.springer.com/article/10.1007/s11709-012-0156-8.
19. Giuseppe Fallacara et al. “An Unfinished Manifesto for Stereotomy 2.0 - Nexus Network Journal.” SpringerLink. Springer International
1112
Publishing, June 11, 2018. https://link.springer.com/article/10.1007/s00004-018-0390-z. 20. Giuseppe Fallacara et al. Stereotomic Design. Maglie: Gioffreda, 2014. B. TECHNOLOGY: Efficient Innovations
C. DIGITAL FABRICATION: Parametric Design
“The geometry of these structures depends largely on a continuous force flow and stress performance of the overall shape, where resilience depends on the precision of modules and joint surfaces and the capacity to resist internal and external forces.”21
Historically, stereotomy has always been explored with stone. However, the fact is that any technique can be adapted on another similar material based on how the material wants to behave, how it can be worked, moulded, and transformed for suitable value propositions through ‘digital stereotomy’.22 It suggests that through digital simulation and rationalised customisation, each module is a unique serial identity whose value is sent to the fabrication platform.
Robots are versatile tools that can be integrated in the design to production process due to its flexibility in both digital and physical modes – from parametric modelling, kinematic simulation, algorithmic program mability, flexible functionality to customisable workflows.
Here, it can be used to discretise the huge volume of variation in module geometry, support material efficiency by maximising stock-production ratio, aid in high-volume quick production by controlling the material plasticity. Its limitations like the tool size and speed, constrained workspace, etc can define man ufacturing stocks and volumes.
fig 10. Flowchart explaining the key intents of the RWC with respect to material, fabrication and geometry: ma terial efficiency, production accuracy, parametric design and mass customisation (bridging craft and technology).
Precise varying cuts, exactitude angular calculations, and the geometric customisation of the modules, set the foundation for ‘digital fabrication’- a mode to constraint the moulding nature of clay to derive complex optimised forms. It brings in reasoning and logic in the manufacturing chain, through the programmed modularity of the components and mechanised design limits.
As the construction material and the geometric modules are adaptable yet discretised, it is important that this specific fabrication platform provides design flexibility but within the limits of manufacturing con straints. Thus, given the uncertainty and the deformability of the material, the need for rationalised custo misation and the demand for stereotomic precision, the digital fabrication system seeks a multi-functional tool (Figure 10).
The adaptive robotic tool also needs to ply with the plastic nature of clay that defines its customisable potential. This approach was initially explored by the Ceramic Lab at the Graduate School of Design (GSD) in 2011.23 It emphasizes on the production of bespoke interlocking low tech assemblies for non-orthogo nal construction (Figure 11a). These types of complex forms either require differentiated mortar joints or expensive scaffolds or high artisanship. This research seeks lessons on design variability through the inte gration of a simple high tech wire cutting system into existing extrusion manufacturing system of ceramics.
While the former project adapts the extrusion process for structural assemblies, the Revolving brick proj ect at GSD24 validated the customisation through the application of thermal behaviour of self-shading façade. Here, the need for the wire cutting process arrives over other manufacturing processes for specific geometries with incremental shape change as it causes most minor low-cost changes in the production cycle, is more efficient and less time consuming. (Figure 11b) By analysing the above projects this RWC research further tries to capitalise on the advantages of this subtractive system especially in its flexibility in producing pocket and partial depth cuts that sometimes involve combination of waterjet and milling.
21. Richard Etlin. “Plaited Stereotomy: Stone Vaults for the Modern World.” Google Books. Aracne. Accessed September 30, 2022. https://books.google.com/books/about/Plaited_Stereotomy.html?id=nQ1yPgAACAAJ.
22. Shayani Fernando et al. 2019. “Towards a Multi-Criteria Framework for Stereotomy – Workflows for Subtractive Fabrication in Complex Geometries.” Journal of Computational Design and Engineering 6 (3): 468–78. https://doi.org/10.1016/j.jcde.2018.07.005.
23. Stefano Andreani et al. “Flowing Matter: Robotic Fabrication of Complex Ceramic Systems.” Proceedings. IAARC, June 29, 2012. https://www.iaarc.org/publications/proceedings_of_the_29th_isarc/flowing_matter_robotic_fabrication_of_complex_ceramic_ systems.html.
24. Andreani, Stefano, and Martin Bechthold. “[r]Evolving Brick:” Fabricate 2014, 2017, 182–91. https://doi.org/10.2307/j.ctt1tp3c5w.26.
fig 11a. Integrating industrial robot within extrusion chain fig 11b. Customisation in wire-cutting prototyping.
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fig 12. Subtractive Machining metrics study compar ing CNC milling with RWC for a series of geometries.
Specifically for architecture of volumes, the compar ative figure 12, shows that this process reduces the production machining hours by tolerating the rougher surfaces smoothly while demoulding.
Moreover, the material removal is not constrained by the depth of the bit, hence it removes the material volumetrically in a single sweep rather than layer by layer, leading to a better surface finish and reducing demoulding adhesion. Other subtractive systems de pend on the unit cost of tooling especially for detailed finishes.25
“All in all, even for prototyping iterations, this method seems efficient especially with automated precision and variability, through parameters like multi-tool application, low waste production, economic affordanc es, and less processing time.”26
The aim of the project is to propose a stereotomic ceramic construction system for post disaster reha bilitation in clay rich seismic contexts. This is achieved by robotic digital fabrication technique of wire cutting clay. This research paper predominantly focusses on the digital fabrication system and the interre lationships between robotic production (the tool), stereotomic geometry (the structure) and wire cutting system (the process) (Figure 13).
D. ROBOTIC WIRE-CUTTING: Aims & Objectives
fig 13. The digital fabrication setup of RWC comprising the three: robotic production (the tool - Kuka KR60), stere otomic geometry (the structure - clay stock) and wire cutting system (the process - steel wire-cutting end effector)
“Assessing the potentials of digital fabrication through a robotic wire cutting workflow for production of stereotomic ceramic assemblies in traditional craft contexts.”
This research tries to develop an integrated workflow for design and manufacture of ceramic modules. Primarily, it studies the contingencies involved in a simple, yet convoluted, contemporary manufacturing workflow that plies on the plasticity of clay, a non-conventional, yet an efficient vernacular building mate rial. It then delves into the intolerances and deformations that affect the ‘adaptability’ of this automated system to achieve material efficiency, production accuracy and geometric customisation? (Figure 14).
25. Wes McGee et al. “Processes for an Architecture of Volume - Researchgate.” Accessed September 30, 2022. https://www.researchgate.net/publication/312804890_Processes_for_an_Architecture_of_Volume.
26. Weir, Simon. “Waterjet and Wire-Cutting Workflows in Stereotomic Practice Material Cutting of Wave Jointed Blocks.” Proceedings of the 22nd Conference on Computer Aided Architectural Design Research in Asia (CAADRIA), January 20, 2022. https://www.academia.edu/en/68894575/WATERJET_AND_WIRE_CUTTING_WORKFLOWS_IN_STEREOTOMIC_PRACTICE_ Material_Cutting_of_Wave_Jointed_Blocks.
fig 14. The thesis objectives for testing the potential of the digital fabrication
The research charts out a series of design investigations using the physical and the digital tool to derive the optimised design and fabrication parameters for stereotomic ceramic assemblies. The preliminary physical tests aim to explore the parameters that define a wire-cutting workflow by studying the flexibility of this process and develop a tectonic system by actively engaging with material explorations.
Before moving onto fabrication, the second step plans to incorporate these construction variables as material information into the digital parametric model. Finally, in the fabrication phase, as per the speci ficities of the construction technique, the research seeks to test an integrated craft-technology approach. Thereby the project explores an interwoven workflow based on material expression – computational complexity – fabrication information to develop a wide reaching, design flexible and a faster pace of pro duction of non-standard modules.
The above-mentioned workflow can be studied under the bracket of ‘robotic stereotomy’27 – “the logic of the structural and material principles is integrated within the rationale of emerging fabrication technolo gies, thus enriching the potential possibilities of digital fabrication-based production.”28
27. Paoletti, Ingrid, and Roberto Stefano Naboni. “Robotics in the Construction Industry: Mass Customization or Digital Crafting?” SpringerLink. Springer Berlin Heidelberg, January 1, 1970. https://link.springer.com/chapter/10.1007/978-3-642-40352-1_37. 28. Oxman, Rivka. 2012. “Informed Tectonics in Material-Based Design.” Design Studies 33 (5): 427–55. https://doi.org/10.1016/j.destud.2012.05.005.
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CHAPTER 01: MATERIAL EFFICIENCY
How does the material state and behaviour define the key parameters of the fabrication process?
Learning from tacit knowledge, it is observed that, using blocks of clay in its fresh state allows craftsmen to insert their carving tools deeper into the material and create smoother surface finishes in single sweep or minimal passes.29
Thus, to test the wire cutting technique in terms of producing undercuts, deep reliefs and achieving bet ter, smoother, larger surface finishes in the least production time, it is important to study the material nature which majorly defines the basic fabrication and geometric parameters.
Preliminary tests were carried out to understand this material response to the tooling technique – how does material removal work effectively in a single sweep rather than layers (Figure 15). Some key empiri cal relations were identified between the material and the tool.
First, the payload of the robot defines the weight of the end-effector, the wire cutter. The length of the wire cutter is proportional to the maximum cross diagonal of the material stock, thereby defining its cross-surface area. The depth of the stock is related to the distance between the TCP (Tool Centre Plane) and the end plane of the robot arm.
Thus, the volume envelope of the material stock is defined by the end-effector dimensions and robot reachability. Now, the first three challenges faced by the material are the surface resolution, geometry de formation and material displacement when simple cuts and setup were acted upon the stock (Figure 16).
Kalo et al. “Robotic
Carving -
https://doi.org/10.52842/conf.caadria.2020.2.443.
a
From the above tests, firstly, it is observed that the geometry deformations during and after the cuts are an area of concern. This is due to the surface friction between the steel wire in motion and the clay ma terial in static mode. One of the research studies attempts to resolve this using high speed oscillation.30 Due to the dense nature of clay, the movement creates a narrow air gap trajectory which allows creation of smooth, fast cuts and achieve tight curvatures which are difficult due to the ‘drag’ effect. In this study, the variation in robotic toolpath is tested with different clay states (fresh, leather hard, green) - Figure 17.
Rossi et al.
(1):
“Oscillating Wire Cutting and Robotic Assembly of Bespoke Acoustic Tile Systems.”
https://doi.org/10.1007/s41693-020-00051-8.
fig 15. Understanding how the tooling boundaries (Robot) relate to the material limits (stock of clay) and its response. fig 16.Identifying ways to tackle accuracy in terms of resolution, displacement and deformation
29. Ammar
Sand
Machining Techniques Derived from
Traditional Balinese Craft.” CAADRIA proceedings, 2020.
30. Gabriella
2021.
Construction Robotics 5
63–72.
1718
17. Geometric deformations due to toolpath motion on different clay states (fresh, fresh+, green, leather hard)
The second key observation is material distortion during demoulding/unmoulding I.e., while separating the positive and the negative workpieces from one another. Here, the wire deflection behaviour and ma terial composition, both affect the shape deviation from the target geometry. The deflection length of the wire is controlled inversely with increasing speed.
Here (in Figure 18), the prototypes are analysed as per the material change (three clays with different shrinkage, moisture, and grog composition), the adhesive nature of the clay defines the material displace ment and geometric deviation while demoulding the negative part from the positive cut stock. The Flow ing Matter Research31 at the GSD suggests that the clay with higher grog content, low shrinkage and high green strength works most effectively for wire cutting. However, the given clay compositions at hand have varying measures of the above three parameters. So, it is important to test a series of constant geometric cutting profiles on these three variants.
3D - Red Earthenware 32
Firing range: 970-1055oC Water content: 25%
Drying shrinkage: 12%
PRAI 3D - StonewareClay 33
Firingrange:1240-1300oC Water content: 22% Drying shrinkage: 8.5%
The fresh state of clay (moisture 75%) produces upto 10mm tolerance changes in Z-direction using simple linear cuts. (as seen in Fig 17. case )
In combination with horizontal zigzag cuts along the perpendicular direction leads to 50% less in distor tion within the boundary limits of 2mm to 5 mm in the perpendicular direction. However, this leads to textured finish for non-planar cuts. (as seen in Fig 17. case )
The green state of clay (moisture 50%) works well with linear cuts with time pauses to avoid friction buildup. This produces least distortion with minimal 2mm tolerance changes in the perpendicular direction using the simple cut itself. This combination uses least speed, minimal plane direction changes and clean finish. (as seen in Fig 17. case )
However, if the clay is in semi-leather hard state (moisture 25%), it is still possible to produce cuts. Here, it shall be used with vertical zigzag cuts along the parallel direction using minimum speed of 3 mm/s and multiple pauses yet leading to 1mm tolerance cuts with basic impressions. (as seen in Fig 17. case )
31. Stefano Andreani et al. “Flowing Matter: Robotic Fabrication of Complex Ceramic Systems.” Proceedings. IAARC, June 29, 2012. https://www.iaarc.org/publications/proceedings_of_the_29th_isarc/flowing_matter_robotic_fabrication_of_complex_ceramic_ systems.html.
32. “PF Red for 3D Printing 5kg.” SIO. Accessed September 30, 2022. https://www.sio-2.com/gb/3d-printing-ceramic-clays/1707-pf-red-3d-5kg-8422830101061.html.
Vulcan Black Stoneware 34
Firingrange:1200-1260 C Water content: 21% Drying shrinkage: 7%
The 3DP red earthenware with shrinkage 12% in the green state shows least material displacement of 7 mm in the perpendicular direction (fig 18, column 02) and geometric deviation of 8mm per sq. mm of surface area (fig 18, column 03)
This provides much ease in demoulding versus the 3DP stoneware with shrinkage 8.5% in the fresh state that shows maximum material displacement of 12 mm in the perpendicular direction (fig 18, col 02) and geometric deviation of 10mm per sq. mm of surface area (fig 18, column 03)
33. “Prai 3d 5kg.” SIO. Accessed September 30, 2022. https://www.sio-2.com/gb/3d-printing-ceramic-clays/1708-prai-3d-5kg-8422830133079.html.
34. “Vulcan Black Stoneware (Fine) 1200-1240C.” Potclays. Accessed September 30, 2022. https://www.potclays.co.uk/vulcan-black-stoneware-(fine)
1920 fig
fig 18. Testing geometric deviation for three clays of varying moisture, shrinkage and firing range.
01 01 02 03 04 02 03 04 PF
The third option that works effectively with low shrinkage, high grog and optimal leather hard stage is the Vulcan stoneware clay with most minimal displacements of 3mm in the parallel direc tion (fig 18, col 02) and geometric deviation of 4mm per sq. mm of surface area (fig 18, col 03).
Although the third scenario seems to be the most suitable option, especially for quick, smooth cuts in complex geometry (tested below). However, given the need for precise interlocking interfaces, the project further works on with the first material-moisture with least grog, optimum speed, and accuracy in the cuts.
The third key criteria are the surface smoothness and the need for post-processing of the geometry. Ini tially, the cutting speed and the work-holding system are defined to understand the impact of different geometries and their respective surface resolutions. The work-holding system is setup using a basic vice in place within the robotic envelope (as shown in figure 19) and a standard tool speed is selected.
With the optimal parameters from the previous tests, four sets of basic geometries from a planar cut to singly curved to spline to doubly curved geometries are cut, to study the surface finish. It was observed that the surface resolutions of the continuously changing surfaces were the most optimum due to control on friction, change in planar angles and edge behaviour interactions.
Special characteristic of this system is the generation of only ‘ruled’ surface geometries. To test this com plexity, the Thin Shell Vaulting project35 tests cutting of twisted planar surfaces. This precedent informs the influence of geometry on material behaviour. Geometrically, more than the range of variability due to the ruled surface phenomenon of the process, the study of the shrinkage behaviour is key.
Studies show differential shrinkage of modules during firing due to this ruled surface. Modules with low surface to volume ratio present less shrinkage than others and those with deep sections show low warp age.36 These inferences from the case studies set base for the tests in defining the limits of the fabrication.
Fabrication platform setup with the standard material parameters in place from the preliminary tests.
The primary intentions of the above experiments are to understand the relationship between the material and the tool. The given clay stock is a soft material, and the tool is a sharp one which can create deep effects, undercuts, remove volumes and varied surface area finishes.
There is a negotiation between the material stiffness and tool motion and thus, it is a physical optimi sation process to define the most optimum fabrication time, geometry scale, thickness, volume, edge definition, moisture for surface quality, resolution for textures and curvatures for complexity (Figure 20).
Maciej Kaczynski et al. “Robotically Fabricated Thin-Shell Vaulting: A Method for the Integration of Multi-Axis Fabrication Processes with Algorithmic Form-Finding Techniques: Semantic Scholar.” January 1, 1970. http://papers.cumincad.org/data/works/att/acadia11_114.content.pdf
Gabriella Rossi et al. 2021. “Oscillating Wire Cutting and Robotic Assembly of Bespoke Acoustic Tile Systems.” Construction Robotics 5 (1): 63–72. https://doi.org/10.1007/s41693-020-00051-8.
fig 19. Achieving optimum material surface resolution by establishing standards in material-fabrication setup. fig 20.
2122 35.
36.
CHAPTER 02: PRODUCTION ACCURACY
How does the precision in the fabrication process inform the geometric behaviour of material?
The digital fabrication process is a workflow between the design and the toolpath. The algorithm was developed on Grasshopper37 that has the flexibility to manage a range of parameters for flexible custo misation. This geometric logic is transferred to the KR60 robot automated fabrication system. The plugin Robots38 was used to generate, simulate, analyse, and optimise motion paths.
This is done by defining the target planes and tool centre plane by taking their position and orientation in real time and translating them into robot code. The toolpaths or the robotic trajectory is then defined by the required sorting and alignment of the planes in order. Similarly, the machine code which acts as guiding lines is generated for varying geometries. However, to make this process more effective, it is im portant to consider the parameters of the automated system as well, like the collision of wire cutter and stock needs to be avoided by limiting the rotating angles along the cutting path, and the digital tool helps to compute this with inverse kinematics.
The lead-in and lead-out movements also define the geometry distortion and displacement at right loca tions. Also, multiple rotation in planes also impacts the precision to the cut. To avoid this, the plane and zone parameters are modified. Hence system customisation (shown in Fig 21).
and curvature.
21. Customisation of the toolpaths as per material form, rotating
37. Grasshopper. (n.d.). Retrieved October 1, 2022, from https://www.grasshopper3d.com/
fig 22. Relationships between geometric accuracy and fabrication parameters of the robotic platform.
As studied, the key inputs for the setup that inform the geometry of the module are the path curves, their relative points, and the target planes which relate to the fabrication limits. Thus, there is relationship between their design and target geometry. Moreover, the simulation as well anticipates this workflow relationship. Therefore, to optimise the process, the geometry can be modulated in accordance with fab rication constraints (Fig 22). One needs to study the adaptability of the physical tooling to understand the geometric limits exploration. The material parameters are kept constant now, like the material moisture, stock volume and cut surface area.
38. Robots. Food4Rhino. (2022, July 31). Retrieved October 1, 2022, from https://www.food4rhino.com/en/app/robots
fig
angles
2324
The key intents are the control of material distortion, geometric deformations, and surface res olution, while a series of sub-intents are to define the fabrication parameters like production time (for high volume and low-cost production), material optimisation (managing stock-geome try ratio and work-holding), manufacturing quality (production precision and tool health control).
To achieve this, sets of geometric tests with given stock volume were done with the following aims:
1. The depth domain within the stock that the tool can reach with sharp cuts with minimal drag.
2. The slope length limits before the geometry deforms upon demoulding.
3. The optimum surface area – interface expanse to avoid adhesion while demoulding.
4. The maximum achievable volume within boundaries without geometric distortion.
5. The angular domain of the volumes to study shear, tension and compression while interlocking.
6. Tool, material, and geometry behaviour with shift in angles, slopes, areas, and volumes.
It was observed that given a stock volume V and an objective to carve out volume v, to achieve a near net volume of at least 90% accuracy, the depth of the cut must be atleast 0.5 to 0.6 fraction of the overall depth. Other aspect that can bring in better accuracy is the tool path sequencing which will limit the drag affecting the geometric edges and corners (Fig.25a)
For ensuring optimal surface quality, it is noted that the surface expanse area depends on the ori entation along or against the stock. The orientation angle above 45o from the +Z direction along the stock and an orientation angle above 90o from the -Z direction against the stock defines clean cuts up to expanses of 0.75 fraction of the total stock length. Alternatively, the control over the robotic tool speed and wait time can aid in achieving steep and larger surface areas (Fig.25a)
fig 25a. Defining geometric limits and domains in relation to the tool and material behaviour
Similarly, the slope lengths majorly depend on the wire tensioning. Since this is an arbitrary parameter, in terms of the tool behaviour, it is relative to the tool trajectory. The count of the target planes and their relative position density is directly proportional to the slope length. However, the slope length also im pacts the edge corners of the cuts. Its’ precision depends on the stock load (material parameter) and the approximation zone (robotic parameter) (Fig.25b)
The next parameter, geometry volume, is a qualitative factor rather than a quantitative one. Its position within the bounding box of the stock defines the ease in tool movement within the stock, ideally from the periphery at an offset of 5mm or 5 to 10% of the stock. On the other hand, multiple passes of the robotic toolpath shall help in bulk stock removal and achieving deep, undercut, & sharp relief volumes (Fig.25b).
fig 24. Data feedback loop: Wire-cutting, Kiln firing, Scanning Tolerance, Interface Checks
2526
fig 23. Ideas to define the geometric limits in response to the tool
fig 26. Key parameters for production accuracy in RWC
fig 25b. Defining geometric limits and domains in relation to the tool and material behaviour
The studies on the angular domain did not produce clear results due to, one, deformations because of the stock lengths and multiple planar re-orientations within every 0.05 fraction of the overall surface cut, two, domino effect of material distortion of one micro-cut to another which builds up exponentially, and three, lack of live feedback between the material and the toolpath which adds up the deformations without giving clarity on the individual angular variations (Fig.25c)
The tool plane orientation change at every point of the geometry is critical to avoid these micro-distor tions. Although the above physical parameters helped define the basic geometric properties that this wire cutting system can work with, now, it is important to study the digital robotic parameters that shall help achieve the limits in the above aims.
fig 25c. Defining geometric limits and domains in relation to the tool and material behaviour
To study the same, one set of geometry was taken constant and a range of parameters, like, toolpath speed, stock volume, toolpath plane orientation, wire strength, work-holding strategy, stock load, approx imation tolerance zone, toolpath resolution, etc were varied one after another to achieve a prototype of minimal geometric deformations and maximum accuracy. (Fig. 27)
Till now, the material and fabrication parameters aided in a strategic RWC with minimal material distor tion, minimal geometric deformations, and maximum surface resolution. To further adapt this system and setup computational parameters for design applications, a series of geometric tests are done at varying scales within the fabrication framework (robotic and material envelope).
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fig 27a. RWC - Fabrication Robotic Parameters fig 27b. RWC - Geometric Parameters
CHAPTER 03: GEOMETRIC CUSTOMISATION
How does the geometric domain and limits of the design define material optimisation?
The above table (Figure 27) enlists the detailed material and fabrication parameters that define the flex ibility and limits of the wire-cutting process. This shall act as guide for geometric explorations. However, it is observed through the preliminary analysis that the digital fabrication system is highly dependent on the material behaviour. At the same time, the motion planning of automation adds in more contingencies like machine acceleration, motion pause and play, etc. This leads to deflection and major change in the trajectory pathway in the process. It is a function of the cutting speed, material loading and wire strength.
The next graphic depict the variation between the digital model, simulation model and the physical model. This graphic provides information on geometric limits and domains of angles, slopes, lengths, ar eas, and volumes in relation to a given material stock and in response to the tool behaviour. (Figure 28)
The conclusions from these geometric limits shall provide feedback into the digital and physical fabrica tion parameters. Given a particular geometry, how can this robotic wire cutting be optimised with a list of logical techniques? Learning from the above conclusions, different logical sequences of toolpaths are developed in accordance with the given geometries. This manufacturing workflow draws parallels from wire-cutting research of EPS (Expanded Polystyrene) foam for concrete casting at Sao Paulo.39
In that research, the gap in the melting of the EPS foam is limited by keeping one parameter of the system constant and accommodating the solution by varying the other parameter. In that project, the speed and the temperature of the wire affected the cutting width, so, at specific turning points like vertices of curves or sharp angles which are prone to local precision loss, say, the temperature is lowered leading to more time in cutting. The low thickness of the material in sections is also studied by compensation of the decid ing parameters. Similar strategies are adapted to optimise this process here. (Figure 29a,b and c)
At the first instance (Figure 29a), it is seen that at the edges, distortions lead to curvatures, and these are directly related to the slope angles at those junctions. For less tolerances here, it is advisable to have sweep horizontal cuts at higher speeds, followed by vertical zigzag cuts in parallel offset to the edge to low er the friction as it goes closer to the target cut. Finally, the target cut can be managed with minimal speed, suitable wait-time relative to each plane and re-orientation of neighbouring tool planes to their normals.
fig 28. Variation between the digital model, simulation model and the physical model to derive toolpaths
39. Campos. Expanding the material possibilities of lightweight prefabrication in concrete through robotic hot-wire cutting - form, texture and composition from https://www.academia.edu/82980120/Expanding_the_Material_Possibilities_of_Lightweight_Prefabri
40.
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cation_in_Concrete_Through_Robotic_Hot_Wire_Cutting_Form_Texture_and_Composition
Ammar Kalo et al. “Robotic Sand Carving - Machining Techniques Derived from a Traditional Balinese Craft.” CAADRIA proceedings, 2020. https://doi.org/10.52842/conf.caadria.2020.2.443.
fig 29a. Toolpath derivation for minimum material distortion
In another instance (Figure 29b), for less deformations in deeper volumes and steeper slope angles, a roughing toolpath type of strategy is employed. Here, multiple passes with equal or incremental offsets are carried out to remove the bulk material from the stock and slowly inch towards the fine target geom etry. For this strategy, the depth and the width of the volume are considered and are proportional to the toolpath offset distance. For volumes where the depth is almost equivalent to the width, it implies steeper slopes, higher target plane density, and therefore for optimal cuts, the offset distance decreases leading to multiple passes with almost equal offset distances. Whereas for volumes with variation in depth versus width, there needs to be balance between removing maximum bulk versus minimum production time. Here, the offset distance increases with minimal passes and incremental offset distances.
In the third instance (Figure 29c), where in, the surface resolution and smoothness are of prime concern due to large surface area expanses, the lead-in and lead-out define the trajectory of the cuts. This is nego tiated by studying the relationship between the surface area and lead-in toolpath offset distances; as well as the relationship between the expanse length and lead-out toolpath slope angle. The lead-in toolpaths ideally run in parallel to expanse lengths with calculated offset distances as the consistency in friction needs to be maintained while the lead-out toolpaths are quick and sharp as it must remove material bulk effectively so that the adhesion does not disrupt the remaining fine material closer to the near net shape.
These strategic toolpath adaptations constituting the material, fabrication and geometric parameters help in charting out well-defined robotic wire-cutting manufacturing pathway for clay/ceramic materials. This further leads to understanding the role of wire cutting workflow for clay in relation to the workflows of other subtractive systems of manufacturing. Robotics based subtractive manufacturing can be kerf or nonkerf based. Kerf is defined as the width of material removed by cutting.40 Kerf-based methods are those where a volume of material is removed in a single pass, while non-kerf-based operations are those where the material is sliced layer by layer tangential to the stock.
fig 29b. Toolpath derivation for minimum geometric deformation.
fig 29c. Toolpath derivation for maximum surface resolution.
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A B C
This research seeks to hybrid both these systems and adapt wire-cutting to clay behaviour. Since it’s ad hesive character challenges the demoulding post-cutting, experiments to mitigate the inaccuracies, in volve both roughing and fine toolpath strategies. This optimises the cutting sequences of wire cutting and deems it an efficient prototyping iteration system for plastic materials like clay. To make this digital fabrication system more efficient, adaptable, and versatile, the following is an attempt to make it a logical, procedural based parametric workflow which is adaptable to a given material composition, fabrication limits and geometric customisation. This is termed as subtractive motion planning for RWC. For example, for this given geometry, these are the key logical steps for optimal cuts through RWC (Figure 30):
fig 31a. Standard Geometric limits - Parameters fig 31b. Test Example - Geometric limits
For given stock volume, identify the target geometry volume, depth, slope lengths, surface areas and an gles. Compare these in proportions to the above limits in the parameters table (Figure 31):
Study the volumetric nature of the geometry. If the ratio of target volume and the stock volume is almost equal to 0.50; target height to stock height is more than 0.50; and residual height is equal to 3/4 overall height; these define the relative position of the target geometry within the stock. Hence, it is observed that it needs around 4 number of roughing cuts parallel to the max. Z height of the target. It is advised to run at max. speed of 8mm/s and tool planes can be continuous in parallel direction for faster, rough cuts.
While studying the volume height and steepness of the slopes, here the height is almost equal to the length of the volume, and therefore, the geometry requires minimal passes with incremental toolpath offsets. These offsets are proportional to the volume height, and it’s offset distance should be around 1/3 times the height. In this case, the speed of the offset cuts is decremental as close to the target geometry to ensure minimal distortion. The change in curvature of the cuts is proportional to the slope angle. This is done to remove the bulk material smoothly.
Now, for the fine toolpaths, a zigzag toolpath motion normal to the planes and about 3mm offset from tar get periphery sets an easy frictional rough base for the final cut. Here, the toolpath resolution is key, the plane count is relative to the angle domain above 180o and hence should be 18. The plane positions are relevant for ease in plane re-orientation. Their location is dependent on the slope length and the toolpath offsets. They are denser at the discontinuous points of the cutting profile for min. tolerances at edges.
For the final cut, the three criteria are the most critical – minimal material distortion, minimal geometric deformation, and maximum surface resolution. Hence, the speed control should be 5mm/s at the dense planes with a wait time of 2 seconds at all planes. Another robotic parameter to be checked is the approx imation zone to be zero. The last aspect is the re-orientation of the planes parallel or perpendicular to the cutting profile as per the slope angle. These key steps help in optimising the fabrication sequence and developing a quality manufactured prototype.
3334 fig 30.
Toolpath methodology
for
a given geometry
CHAPTER 04: DESIGN APPLICATIONS
How can this digital fabrication method be applied for the manufacture of interlocking ceramic bricks in a stereotomic context with the need for accurate interfaces for structural stability? For the same, how does the above learnt material and fabrication parameters control the geometric limits of the design?
The above physical and digital tests help manage fabrication tolerances. These strict tolerances are re quired for stereotomic assemblies. The accuracy at the interface cuts helps the modules self-support in as sembly. Dimensional and angular deviations will lead to local stress failures, can affect overall form assem bly and structural instability of the macro-structure. The research attempts to relate back to the context and rethinks on the design of macro-structure as a structurally performative response to the unreinforced Bhunga masonry forms. With the focus on robotic stereotomy, this can be achieved through self-support ing structures with interlocking modules. They are monolithic construction where the position of modules and their joints are the driving structural forces without the need for mortars or connectors.
The geometry was designed within the limits of the given volume of stock and the target geometry was 25% of the stock. Key elements are slope angles which were in the range of 45o to 125o for ease in plane re-orientations and setting up lead-in and lead-out trajectories. The module is achieved in 3 minutes production time with 8 roughing and 6 finishing toolpath passes. The rest of the parameters are enlisted in the table. On digital scanning and overlay, it is studied that the geometric accuracy is 85%. The issues faced were at the inclined edges and interface locations. (Figure 32)
fig 33. Module assembly logic with digital fabrication and application perspective
The next step is to develop the logic for assembly as per the geometric interlocking behaviour. From the conclusions of design and fabrication of 1D modules, the assembly investigates 2D and 2.5D module ag gregations trying to seek balance, on one hand, the assembly behaviour due to its orientation, porosity, and direction, and on the other hand, the efficiency of fabrication. Beyond this, the 3D assembly aggrega tions were developed for longitudinal, transverse, and diagonal growth systems development. From the digital fabrication point of view, the critical aspect to be considered here is the efficiency of the interface, again with the aims of surface resolution, geometric deformations, and material distortions.
fig 32. Module design and definition of the geometric parameters for RWC and toolpath development
Learning from the principles of topological interlocking, and design parameters like robot limits, minimum waste, optimised material use, minimum time, structural stability, easy assembly, minimum joinery, etc, a basic brick module was developed using the methodology and several ways to cut the brick from the stock.
Moreover, as discussed earlier, the interface is important for the stress distribution and static equilibrium in the structure. This research intends to study a novel tectonic within this geometry of the interface. Through tests with series of planar and non-planar edge faces, it is strategic to observe how the ruled interfaces resist each other through counter forces and avoid failure.
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As they stagger and cantilever, how does the moment force that shifts the module out of place is counter acted by the shear forces of the ruled geometry? How is the module interlocked and what is the impact of their self-weight on supporting each other? The detailing of the module requires understanding of the joint geometry as well. Studies show that three-dimensional joints can resist shear, torsion, and vertical com pressive forces. Can variation of planarity and curvature across the interfaces aid in efficient interlocking?
“Structural studies of sinusoidal, catenary, and hyperbolic curvature show influence of geometry under shear and compression. They also aid in the flexibility and movement of joints against rigid fixed connec tions.”41 However, before optimising the basic module with these non-planar interfaces, it is important to note the material behaviour at the interfaces with these variations, especially, the contingencies of mate rial drying, shrinkage effects after firing and the overall impact on the assembly. Thus, the interface studies were done from planar semi-circular curves to doubly curved hyperbolics.42
On drying, it was observed that for a given stock volume of 120mm x 120mm x 120mm; the geometries with curvature until 0.2 mm-1 showed the least tolerance of about 2mm to 5mm. These included semi-circular cuts under both single and doubly curved category and hyperbolic curves under the non-planar ones. The stateof-the-art research as read earlier shows that structurally a doubly curved interface (non-planar) is more efficient. Upon scanning and checking shrinkage post firing, the gradual curves of hyperbolic paraboloid in terfaces show minimum assembly
due to uniform shrinkage along and away from the curved profile.
3738 fig 35. Interface tests with scan overlay to observe shrinkage, deformation fig 34. Vertical Compression Results for goemetric variationsFEM Analysis
issues
41. D Reinhardt et al. (2017, November 1). Simulating self supporting structures. Academia.edu. Retrieved October 1, 2022, from https://www.academia.edu/34883840/Simulating_Self_Supporting_Structures 42. E. Erdine et al.Robot-Aided Fabrication of Materially Efficient Complex Concrete Assemblies | Semantic Scholar. https://www.semanticscholar.org/paper/Robot-Aided-Fabrication-of-Materially-Efficient-ErdineShowkatbakhsh/3d247ce0699ca0621d08f56bbe66679fd2ee9882/figure/16
The assemblies were incorporated with the hyperbolic paraboloid at the interface and one of the 2.5D aggregation is selected. A subtractive motion planning flowchart is developed to sequence every cut by evaluating the material, fabrication, and computational parameters. This exercise is evaluated based on geometric deformations, material distortions and surface tolerances.
The roughing toolpath sequence of fabrication of 3 passes with 5 mm offsets and toolpath plane ori entations as per the slope length and angle has helped in defining smooth surface finishes at the cuts. The material moisture level in combination with the toolpath speed and zig-zag motion definition aids in achieving 90% accuracy while assessing material distortion. Comparing with the parameters chart of the geometric limits, the angular domain of 90o to 120o helps in smooth lead-in, target, and lead-out plane alignment within a maximum movement range of 3mm/s to 8mm/s which avoids deformations especially at edges and corners.
Technically, a few drawbacks were observed which if resolved, can further optimise the digital fabrication process. Some specific cuts are difficult due to the non-reachability of the robotic arm and to counter-act the same, the stock volume and position needs to be adjusted with re-calibrations to be done for fabrica tion of every new module. This can be resolved by using the turntable as external axes of the robot arm and more robust work-holding on the same for optimising the manufacturing process with further precision.
Along with these physical fabrication solutions, some digital solutions can be applied to the process like ro botic toolpath sequence optimisation using applications like PyRAPID that clusters all the cuts into a single sweeping motion and computes the toolpath movement by optimising the robot reachability. Further, the most efficient future step to make this digital fabrication more adaptable to the context is parametrising it.
Overall, the design of the modules, its interfaces, its assembly logic, all of these define the tectonics of the system as per the material behaviour and fabrication response. However, the interesting feature of this method is its customised individual modules as a product of the given automated tooling and dig ital fabrication platform. Thus, this research proposes an integrated digital-physical workflow that com bines material and manufacturing logic to optimise the design and fabrication of complex geometries.
3940 fig
36b. Hyperbolic Paraboloid Interfaces in module geometry for RWCfig 36a. Exploded module design
fig 37a. RWC Fabrication for cut-volume module fig 37b. Assembly setup and individual target geometry
CONCLUDING DISCUSSION
The simple tools of wire cutting are automated to create a quick production system for high volume-mass customisation of ceramic geometries. The research attempted to assess the potential of this system which involved expanding on the flexibility of the robotic tool, the complexity of the geometry and the control on the material behaviour. Geometric adaptation in response to the limits and constraints of the material, and fabrication parameters in the context of architectural ceramics encapsulates the design for manufacture workflow exploration in the thesis. However, the challenge that this digital fabrication process faces is to seek ‘adaptable’ value of the workflow in terms of the context needs, the application of the customised potential of technology in a low-tech economy and its integration with the craft.
In other words, the Final Major Project that takes forward this research seeks to evaluate the non-ob ject-oriented values of the digital-physical workflow. The research, initially, establishes its value proposi tion through contextualisation of architectural ceramics by resourcing local clay construction in rural India. It then establishes its utilisation in the context by reinforcing the structural performance of traditional houses through the production of stereotomic modules via the robotic wire cutting process. This journey, thus, involves a study of the symbiotic relationship of craft and technology – a balance of low-tech resourc es and high-tech fabrication solutions. Further, this process has the potential to provide social, economic, and sustainable value with multiple objectives.
The project can propose a techno-social integration in the context with the idea of ‘industrialised craft’ in the production cycle. It can involve social assessments of the contexts and an evaluation of the benefit of the process by seeking its integral position in the manufacturing industry, for example, development of a bespoke mass-customised market for this manufacturing process. It can also be positioning this fabrica tion process in the existing manufacturing pipeline that overcome the challenges of the economy, where the local labour can be supported with the technology, and the design-to-production workflows can help resolve social problems and serve an architectural or environmental purpose.
For example, for the given context, the digital fabrication system can also be used for environmental goals by applying the traditional bioclimatic principles. With the development of digital analytical tooling and ability to detect tolerances, the process effectively allows control both the material behaviour and geo metric exploration in addition to aiming for performative goals with economical manufacturing system of customised modules.
The open framework platform of robotics and the feedback loop intensifies its capabilities and extends its limits towards bespoke design applications. On the technical front, the process has the feasibility to further explore the limits of the multi-axis. Its adaptive nature in terms of motion trajectory and toolpath development works in symbiosis with the material response. There are applications that can be explored to optimize the automation further that considers the maximum reachability of the tool and configures inverse kinematics toolpath from there. The multiple degrees of freedom push it a step closer to behaviour of the craftsmen than a conventional machine. However, the need for roughening and finishing toolpaths reconnects to existing manufacturing platforms, all to achieve optimisation and efficacy.
Overall, this digital fabrication process tries to define novel ways to process earthen materials. However, they can further be improvised or adapted with other manufacturing techniques to extend its geometric capabilities as well, for instance, to allow more sectional or internal voids, or produce the most efficient cut per unit cost of tooling, or to necessitate minimum stockholding or production of varying thicknesses as per the material state change or so on. These technical options can prove the versatility of the given material, geometry, and the fabrication process for varied applications.
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fig 38a. Changing toolpath motion trajectory across the cutting interface fig 38b. Target geometry vs volume
LIST OF ILLUSTRATIONS
Fig 01 (clockwise from left)
01a. ‘Vernacular Ceramics’. Video Direction by Macarena Alvarado, Diego Aravena from BASE studio, “Flocking Tejas. Vimeo, 2022.”, https://vimeo.com/221798735.
01b. ‘Digital Making’. Interview with Mario Carpo, DigitalFUTURES world. “DigitalFUTURES: Architecture and Automation, YouTube, 2020.
01c. ‘Physical & Digital Tools’. Research Paper by Wibranek, Bastian, et al. “Interactive Assemblies: Man-Machine Collaboration through Building Components for As-Built Digital Models.”
01d. ‘Architecture of Volumes’. Illustration from De La Rue, “Traitè de la Coupe des Pierres, 1728.”, pl. XXX (detail)
01e. ‘Robotic cera-Cutting’. Photograph by Harsh Manish Shah, Bartlett School of Architecture, UCL, London.
01f. ‘Value Proposition through meaning’. Quote from article by Michael Amundsen. “Q&A With Juhani Pallasmaa on Architecture, Aesthetics of Atmospheres and the Passage of Time.”
Fig. 02. ‘The need for accuracy in material uncertainty’. Photograph and Digital Scan by Harsh Manish Shah, Bartlett School of Architecture, UCL, London.
Fig. 03. ‘Craft and Technology’. Illustration by Harsh Manish Shah, Bartlett School of Architecture, UCL.
Fig. 04. ‘Craft and Technology’. Illustration by Harsh Manish Shah, Bartlett School of Architecture, UCL.
Fig. 05. ‘Interdependencies: Material, Geometry & Fabrication’. Illustration by Harsh Manish Shah, Bartlett School of Architecture, UCL, London.
Fig 06. Interview by Ken De Cooman, “Down to Earth: Earth Building in Europe and Africa by BC Architects & Materials Studies.” Architectural Review.
06a. ‘Contemporary Architects’. Photograph by Dieter van Canegham, showcasing Workshop by BC Architects on rammed earth objects for the Oslo Architecture Triennale 2019.
06b. ‘Contemporary Architects’. Photograph Courtesy to BC Architects and Studies, showcasing craftsmen plastering an adobe wall with earth and lime mixture.
Fig 07. Research Studies by Priya Shah, “Ludiya: Partnering with People an Effort in Redevelopment with Community Participation.” Community Redevelopment | Ludiya. Accessed September 30, 2022.
07a and 07b. ‘Seismic resilient craft constructs’. Drawings by the Environment Design Team : Vastu-Shilpa Foundation explaining the vernacular construction technology using local materials.
07c and 07d. ‘Seismic resilient craft constructs’. Photographs by the Principal Non-Governmental Organisation: Manav Sadhana presenting the design, cultural context of the traditional forms.
Fig. 08a. ‘Structural Efficiency of Interlocking Joints’. Technical Analysis Diagrams by A. Borhani, N. Kalantar. “Interlocking Shell Transforming a Block of Material into a Self-Standing Structure with No Waste.”
Fig 08b. ‘Tetrehedron Configuration with Interlocking properties’. Conceptual Illustrations by Oliver Tessmann in “Interlocking Manifold Kinematically Constrained Multi-Material Systems.” SpringerLink. Springer
Fig 09a. ‘Classical Stereotomy’. J. Drawing of Abeille’s flat vault patent in Recueil des Machines Academie Royale des Sciences, Paris 1699.
Fig 09b. ‘Topological Interlocking Iterations’. Drawings in “Topological Interlocking Assemblies: Semantic Scholar.” January 1, 1970. https://www.semanticscholar.org/paper/Topological-InterlockingAssemblies-Tessmann/c0464ffb775059f7e1f0ad856164d60307832d23.
Fig 09c. ‘Adaptation of Stereotomic Production’ Illustrations and Photographs by Giuseppe Fallacara in “Toward a Stereotomic Design: Experimental Constructions and Didactic Experiences.”
Fig 10. ‘Key Intents of RWC’. Flowchart by Harsh Manish Shah, Bartlett School of Architecture, UCL, London
Fig 11a and 11b. ‘RWC – State of the Art’. Diagrams by Andreani, Stefano, and Martin Bechthold in “[r]Evolving Brick:” Fabricate 2014, 2017, 182–91. https://doi.org/10.2307/j.ctt1tp3c5w.26.
Fig 12. ‘Subtractive Machining Metrics’. Study Table by Wes McGee et al. in “Processes for an Architecture of Volume - Researchgate.” Accessed September 30, 2022. https://www.researchgate.net/publication/312804890_Processes_for_an_Architecture_of_Volume
Fig 13. ‘Digital Fabrication Setup of RWC’. Photograph by Harsh Manish Shah, BSA, UCL
Fig 14. ‘Thesis Objectives’. Illustration by Harsh Manish Shah, BSA, UCL
Fig 15. ‘Material-Tool: Empirical Relations’. Illustration by Harsh Manish Shah, BSA, UCL
Fig 16. ‘Key Material Parameters’. Illustration by Harsh Manish Shah, BSA, UCL
Fig 17. ‘Material Deformations Study’. Illustration by Harsh Manish Shah, BSA, UCL
Fig 18. ‘Geometric Deviations – Material Study’. Illustration by Harsh Manish Shah, BSA, UCL
Fig 19. ‘Surface Resolution: Material-Tool Behaviour’. Illustration by Harsh Manish Shah, BSA, UCL
Fig 20. ‘Fabrication Setup’. Illustration and Photograph by Harsh Manish Shah, BSA, UCL
Fig 21. ‘Customisation of Toolpath’. Illustration and Photograph by Harsh Manish Shah, BSA, UCL
Fig 22. ‘Geometric Accuracy & Fabrication’. Illustration and Photograph by Harsh Manish Shah, BSA, UCL
Fig 23. ‘Ideas – Geometric Limits’. Illustration by Harsh Manish Shah, BSA, UCL
Fig 24. ‘Data Feedback Loop’. Photographs by Harsh Manish Shah, BSA, UCL
Fig 25a, 25b, 25c. ‘Geometric Limits and Domains’. Illustration, Photograph by Harsh Manish Shah, BSA, UCL
Fig 26. ‘Production Accuracy Parameters’. Illustration by Harsh Manish Shah, BSA, UCL
Fig 27a. ‘Fabrication Robotic Parameters’. Illustration by Harsh Manish Shah, BSA, UCL
Fig 27b. ‘Geometric Parameters’. Illustration by Harsh Manish Shah, BSA, UCL
Fig 28. ‘Variation between the digital model, simulation model and the physical model.’ Illustration by Harsh Manish Shah, BSA, UCL
Fig 29a. ‘Toolpath derivation for minimum material distortion.’ Illustration by Harsh Manish Shah, BSA, UCL
Fig 29b. ‘Toolpath derivation for minimum geometric deformation.’ Illustration by Harsh Manish Shah, BSA, UCL
Fig 29c. ‘Toolpath derivation for maximum surface resolution.’ Illustration by Harsh Manish Shah, BSA, UCL
Fig 30. ‘Toolpath methodology.’ Illustration by Harsh Manish Shah, BSA, UCL
Fig 31a. ‘Standard Geometric limits - Parameters.’ Illustration by Harsh Manish Shah, BSA, UCL
Fig 31b. ‘Test Example - Geometric limits.’ Illustration by Harsh Manish Shah, BSA, UCL
Fig 32. ‘Module Design & Development.’ Illustration by Harsh Manish Shah, BSA, UCL
Fig 33. ‘Module Assembly.’ Photograph and Illustration by Harsh Manish Shah, BSA, UCL
Fig 34. ‘Interface: Structural Analysis.’ Studies by D. Reinhardt, Weir, S. and Fernando, S. (2017, November 1). Simulating self supporting structures. Academia.edu. Retrieved October 1, 2022, from https://www.academia.edu/34883840/Simulating_Self_Supporting_Structures
Fig 35. ‘Interface Tests.’ Photograph and Scans by Harsh Manish Shah, BSA, UCL
Fig 36a. ‘Exploded Module Design.’ Diagrams by Harsh Manish Shah, BSA, UCL
Fig 36b. ‘Hyperbolic Paraboloid Interfaces.’ Diagrams by Harsh Manish Shah, BSA, UCL
Fig 37a. ‘RWC Fabrication Setup.’ Photograph by Harsh Manish Shah, BSA, UCL
Fig 37b. ‘Assembly Setup & Individual Target Geometry.’ Illustration by Harsh Manish Shah, BSA, UCL
Fig 38a. ‘Changing toolpath motion trajectory.’ Diagram by Harsh Manish Shah, BSA, UCL
38b. ‘Target geometry vs volume.’
by Harsh Manish Shah, BSA, UCL
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Photograph
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Fernando, Shayani, S. Weir, Dagmar Reinhardt, and Adam Hannouch. 2019. “Towards a Multi-Criteria Framework for Stereotomy – Workflows for Subtractive Fabrication in Complex Geometries.” Journal of Computational Design and Engineering 6 (3): 468–78. https://doi.org/10.1016/j.jcde.2018.07.005.
Flöry, S., and Pottmann, H. “Ruled Surfaces for Rationalization and Design in Architecture, in A. Sprecher, S. Yeshayahu and P. Lorenzo-Eiroa (eds.), LIFE in:formation. On Responsive Information and Variations”, 103. ACADIA, 2010.
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