Chapter 1 | Session 1B

Inter-scalar Tomography in Variable Formwork

Chapter 1 | Session 1B

Solid, Surface, Space: Inter-scaler Tomography in Variable Formwork

Naomi Frangos a a

School of Architecture and Design, New York Institute of Technology, Old Westbury, New York, USA

Abstract Over the last three decades, manual manipulation as a design tool has largely been overshadowed by computerized command driven methods of form finding. Coding of sequenced operations allows for an ever-enlarged set of choices in design variability, yet demands the designer to make more decisions a priori, dictating a more predetermined than generative design process. While digital modalities of form seeking appear to offer control over design flexibility, what advanced computer modeling seems to resist is the play from bodily engagement that bridges imagination, as well as cognitive and spatial perception. In response, this paper explores strategies in design teaching that oscillate between analog and digital investigations to engage a type of lateral thinking through various design operations that exist between product and process, or, as Manuel DeLanda argues in New Materialism, “being and becoming.” Examining the interrelationship between virtual and actual, the translation of solid forms into spatial experiences is made through analysis and interpretation of inter-scalar architecture. Within the context of an architectural prototyping course, explorations in flexible formwork design using plastic materials and the resulting cast pieces are used to study variable forms where design thinking is informed by direct material transformation from the hand in constant dialogue with the mind. Bodily gestures are captured in plastic explorations that naturally take form through forces of gravity, weight of substance, and dynamic physical interaction allowing material intuition to occur. Blending analog and digital methods in form finding, small-scale plaster cast studies are 3D scanned to produce virtual models to be reconsidered as wire-frame shells. Sectional slices are extracted and by interpreting the tomographies at various scales an exploration can take place in terms of inhabitable realities. Actual cutting with physical tools would alter the piece in a fixed act at the same scale, not allowing for variable considerations and iterations, whereas slicing the virtual model allows the cutting plane to be shifted and multiple tomographies can be taken in several directions, at the same time, transforming the viewing plane. Fabric forming techniques and formwork design are then re-thought through a type of generative material exploration that considers multiple scales, sites, and conditions. This inter-scalar thinking opens up the possibility of how to visualize 3D space beyond a simple representation, and how to think critically about shapes and forms that can be re-imagined as architecture, landscape, interiors, furniture, components, or details.

Keywords Inter-scalar; tomography; 3D scanning; data-capture; fabric formwork; variable design.

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Inter-scalar Tomography in Variable Formwork

1. Introduction Current tendencies in design, particularly the desire for the variability of complex geometric forms, tend to rely on algorithmic modeling to generate formal options, rather than considering in-between moments of design inquiry and material transformations with parameters still in flux. Bottom-up processes informed by physical engagement with material deal with variation in a different way, where fixing constants is directly related to immediate and deliberate acts of fabrication. This is nonexistent in computational design, since algorithms use a formalized top-down method from the input of a finite sequence of instructions to produce variable outputs, which typically do not consider physical manipulation, contextual factors, or material behavioral properties. As argued by phenomenologists and computational theorists, conceptualizing technology in this way seems to dismiss the shaping of form that comes with embodied sense-based material knowledge. Physical form-finding requires a willingness for risk and experimentation through haptic experience (Pallasmaa, 2009) while treating materiality as an active agent for generating design maintains a connection to a designer’s intuition (Menges, 2011). Interestingly today, data from material responses in making-processes of actual models is being translated digitally into virtual models and used to provide a feedback loop for altering design decisions. This approach can assist in determining how to adjust constants and how to elect variables in an informed generative way. This paper examines material driven form-finding methods and design speculation stemming from blending open-ended and computational design processes in the aim to amplify dynamic relationships between process and product. In particular, it explores variable flexible formwork design informed by direct material transformation of plaster cast models. Digitizing data captured from actual casts by 3D scanning, the object is then visualized in the virtual environment as sequential 2D sectional views taken across forms to record variation in surface profiles and examine scalar possibilities of complex spatial geometries. A series of exercises aims to uncover potential in the design of variable systems through the study and visualization of incremental moments of formal discovery in material transformation. Rather than being representational, the cast studies and their 2D representations serve to disrupt the static time of actual objects “being” and prioritize discovery and analysis of form and its translations “becoming”. “Becoming”, or “middleness” in generative systems is fundamental in physical relationships of an object and its creation (Kwinter, 2002). Here, the analysis of form permits inter-scalar thinking of solid,

surface and space to consider the final scale of production and desired variability in formwork design.

2. Background 2.1. Hybrid Processes: Actual and Virtual Models In the early 90’s, Ghery Partners translated gestural design-sketch models into full-scale mock ups to study the relationship between material, form, and fabrication strategies. Through preliminary 3D scanning methods at the time (Faro digitizing arm) to capture surface geometries and CATIA software to convert these into virtual models, they pioneered digitization techniques in the aim of rationalizing complex analog forms into constructible geometries (Sheldon, 2002). While a hybrid process was key in decoding geometries for developing and manufacturing realizable component assemblies, the hand-made artifact remained the generator of design intent beyond the representation of an idea or the simulation for the reconstruction of something larger.

2.2. Scaling Up Models Using Gravity Scaled models have been a fundamental mode of understanding complex geometries in architectural design for centuries, yet, the possibility of understanding structural resolution has proven more obvious using certain modeling methods. As Gaudi had discovered, actual physical models that incorporated gravity to test naturally occurring curved geometries were easily adaptable to large scale structures of architectural forms. Similarly, using entirely analog methods of casting, Mark West at his C.A.S.T lab found that flexible formwork techniques that consider gravity are a reliable method of scaling up. He discovered that the properties of plaster are synonymous with concrete in maintaining their structural integrity and formal qualities. By quantifying results through physical analysis similar to the actual model constructions of Heinz Isler, students in his graduate studio experimented with creating wall panels and surface patterns, successfully “scaling-up” small plaster tests into full scale concrete forms without any notable deviation from the small-scale designs (West and Araya, 2009). As form-finding was purely analog to begin with and finite element analysis through digital modeling was used only afterwards to study structural analysis and dimensions of the formwork at the small scale, there was no digitization of technique. Although the structuring of surface deformations offered variable outputs, freedom in design expression was explored in an open-ended fashion without analog or digital computational methods as design drivers for adjustable mold design.

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Inter-scalar Tomography in Variable Formwork

2.3. Flexible Formwork and Variability

3. Theoretical Framework and Methodology

As noted by Chandler, casting is no longer a process of replication (Chandler, 2017). By its nature, fabric used as molds for casting lends itself to an analog method with a high potential to yield variable forms. West also discovered that flexible sheets can be easily formed into variable-section beams according to their bending curves, however, his method focused on testing structural optimization rather than modulating variability in formwork design. Alternatively, Modular Variations I and II (Marcus, 2014) challenge contemporary computational design through physical prototyping of reconfigurable mold systems for casting plaster and concrete wall assemblies with varying degrees of apertures. Variations I explored a series of stackable molds whose variability is visualized through a sequence of sections that can be rearranged to produce differentiating modules. This analog method was leveraged parametrically in a virtual model to study overall patterns of units coming together as a wall assembly. In Variations II, varying degrees of twisting in a flexible mold control and calibrate the variation of individual repetitive modules, again using digital computation to facilitate design iterations of the overall composition of units, rather than determine them. Similarly, P-Wall (Matsys, 2006) standardized a flexible formed panel size where the surface variations are uniquely determined by analog patterns of point forces made by wood dowels acting on the fabric and gravity from the weight of plaster with computation reserved for aggregation strategies and aesthetic patterns.

3.1. Theoretical Framework

2.4. Visualization and 3D Data Capture Currently, some researchers are using contemporary photogrammetric data capture techniques to digitize fabric formed models and investigate relationships between material, surface, and form. One study explored real-time 3D scanning with the use of Parrot drones to capture progressive stages of analog construction as a feedback loop for structural optimization in the virtual model. (Chaltiel, Bravo, Chronis, 2017). Another study combined 3D scanning with motion sensors to record dynamic relaxation during actual casting and compares analog results of material behavior to virtual simulations of fabric as a geometric matrix of points loaded with the numerical weight of plaster. Superimposition of the 2 sets of data was explored to predict cast results and reduce discrepancies between virtual and actual values (Prousalidou, 2012). A third study aimed at analyzing curves using same source geometry to maintain original morphologies of cast forms and structural integrity in 3D printed replicas (Becker, 2014).

Considering the recent applications of data capture, it is debatable whether trending hybrid design processes involving digitization of physical models offer design opportunities beyond simulating material formation, mimicking natural forces, or optimizing form through replication. As an attempt to critically explore the possibilities of “becoming” to inform design, the theoretical framework for this paper asks if the data capture of models could also serve to augment design discovery revealed through material studies and analysis of digitization rather than being dictated by it. Since “the model both concretizes and externalizes ideas: its frequently diminutive scale of the model and the observer’s externality invites and permits the identification and judgement of aspects that could otherwise be lost.” (Pallasmaa, 2009).

3.2. Methodology An experimental method was employed that moved between actual and virtual modalities. This method will be evaluated for its facility to better understand 1. the particular moments of deformation in the cast surface; 2. whether variations can be tracked and reworked through the redesign of formwork and yield results that are more rigorous in controlling desired variable parameters, and; 3. how the different scales might operate to produce a final full-scale work.

4. Practical Exercises 4.1. Gestural Sketches and Action Words Initial ideas for how fabric could move were generated from selecting action and context words from the Richard Serra’s verb list and translating them as gestural charcoal sketches. Using the infinite form of the verb, i.e. to weave, in relation to a situational word, i.e. of gravity, emphasizes making by enacting a gesture rather than the imperative verb form found digital software, i.e. stretch, which instructs an operation and demands spatial positioning in the x,y,z axes.

4.2. Variable Formwork Design As a form-finding strategy that could generate variability, enacted gestures became the agent of mobility. 6”x6” wood frames and posts were used as supports to stretch or suspend fabric. Using only string to guide movement and displacement of the fabric, pushing, pulling and penetrating the cloth as point and line forces against the planar fabric created surfaces and volumes when loaded with plaster. Increasing structural complexity of forms were explored: one-sided topographies, two-sided free-

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Inter-scalar Tomography in Variable Formwork

standing surfaces, folded surfaces, and voided surfaces. Figure 2. Plaster Casts The addition of adverbs or adjectives were used to consider levels of intensity or incremental degrees of change in the string-fabric relationship to generate variations. Plastic explorations naturally hardening and taking form through forces of gravity, weight of substance, and dynamic physical interaction allowed material intuition to occur. Through iterations, successes, and failures, intriguing moments in the resulting plaster casts offered insights for setting up more rigorous parameters to control variable outputs, while also letting the fabric to also respond naturally to the plaster. Figure 1. Gestural Charcoal Sketches and Formwork Using String and Fabric.

4.3. Data Capture Using 3D Scanning 3D scanning techniques were employed for data capture of plaster cast forms to produce representational 3D virtual models. NextEngine desktop scanner and handheld Structure Sensor scanner connected to an iPad were both used depending on size and shape of original model. While NextEngine offered more precision at one hundred micron and also allowed number of segments along the surface to be indicated, scanned separately, then merged to reconstruct the whole using proprietary software, exactitude was not critical since the goal was not to create a reproduction, therefore the handheld scanner was used in most cases.

4.4. Visualization as Virtual Models As scale-less objects lacking orientation, actual models and their virtual representations opened up the interpretive nature of material studies. Simply for quick visualization, the 3D scan file was imported into Sli3er and exported as an .stl into Meshmixer, (software for translating virtual models in 3D printing files) to create

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Inter-scalar Tomography in Variable Formwork

slices. This test was performed to understand the limitations of design inquiry using this software. First, the digital model is scaled up randomly to be visible on the printing bed, and second, it must be given dimensions related to the limitations of a 3D printer where the slices could be a constructed at a fixed scale.

Figure 4. Process from Original Fabric Form Plaster Cast to Inter-scalar Interpretations. Project by Erik Jakob.

To explore and manipulate the form beyond its replication, the 3D scan file was imported into RhinoÓ as an .obj which resulted as a mesh and converted into a surface using commands meshtonurbs or drape. As a cast form, the surface qualities of plaster can be enjoyed as an object. By digitizing its form and viewing it as a mesh, spatial opportunities reveal themselves. After achieving a workable poly-surface, the contour command was used to create slices across the model in all directions in the x, y, and z axes. Figure 3. Data Capture with 3D Scanning Techniques and Visualization

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Inter-scalar Tomography in Variable Formwork

4.5. Visualization as Tomographies Digitizing actual models and slicing through mass virtually as a series of tomographies was a way to break down surface variation incrementally, visualize and track its deformations, and consider spatial orientation of form. Thickness of each slice or distances between slices could be indicated to explore profiles further, either individually or as an exploded axonometric of the whole. Figure 5. Inter-scalar Interpretations. (Tim Greening).

imaginable patterns for assemblies. Viewed as a series of sectional cuts with the rest of the form intact invited the idea of an inhabitable variable interior void that continued throughout a much larger elongated form. Combined in repetition to create a continual undulating surface, the form also became a miniature landscape or fragment of a larger landform to be occupied by many. Figure 6. Sectional Studies from 3d Scan of Fabric Form Plaster Cast. (Ben Sather).

4.8. Formwork Design and Re-design

4.6. Scaler Interpretations of Form The first interpretation of scale was explored using the entire virtual model as form. The notion of “Inhabiting Surface” was introduced, and occupiable spatial qualities were explored without preconceived ideas of function or site at 3 scales indexing the body, a room, and a landscape. The mesh invited abstractions that were concretized as spatial forms where the engaged human figure was in motion or seemingly able to adjust their position to fit multiple conditions.

4.7. Scaler Interpretations of Section Using the command make 2D, objects were exported into Illustrator for re-imagining segments with respect to surface qualities and spatial possibilities. Extracted tomographies and details of particular interest were selected, interpreted and explored in terms of inhabitable realities at the same 3 scales as before. At times, the mesh became a thin shell structure, at others a fragment of something larger.

The various explorations led to a more controlled set of parameters for designing variable formwork using concrete as the plastic material, rigid rods as point and line forces to structure the fabric, and formwork dimensions of 6”x6”x18”. Here, a set of points aims to manipulate surface deformation within a repetitive unit. The resulting profiles created by the points and sewn fabric bag revealed a lack of control over parameters with gravity overtaking the design and any regularity lost. The casting of a larger model and exhaustive tomographic exercises taken in multiple axes, combined with a series of transformations on individual segments offered a much more compelling exploration in terms of scale, orientation, and resolution of a desirable profile. Particular sections with similarities were extracted and lofted together to simplify the shape of a new form. Formwork was then redesigned to attempt to control a modular unit design that could be manipulated through the variable formwork to create a series of forms, that when placed together, their matching adjacencies could find alignments as an aggregated whole. Figure 7. Formwork Design, Fabric Form Cast Concrete, Sectional Studies from 3d Scan, Inter-scalar Interpretations. (Ben Sather).

Using operations and transformations such as copy, rotate, and mirror permitted exploration of the mesh at the scale of a variable building component, suggesting

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Inter-scalar Tomography in Variable Formwork

Figure 8. Formwork Re-design Based on Sectional Studies. (Ben Sather).

Figure 9. Formwork Design, Fabric Form Cast Concrete, Sectional Studies from 3d Scan and Virtual Model. (Emily Black and Andres Carcamo).

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Inter-scalar Tomography in Variable Formwork

Creating a 3D cage with points that could be manipulated in various directions emulated the idea of points and line forces in the virtual realm that could then be reconsidered in the actual model. While this model remained an idealization of form, without consideration of weight and materiality, the visualization of possible outcomes from clearly defining controlled movements acted as agency for rethinking variable formwork design. Figure 10. Formwork Re-design Based on Sectional Studies. (Emily Black, Andres Carcamo).

profiles, it was easier to decipher which parts responded more successfully to the intention of formwork design, while also revealing which areas related to natural material behavior, such as gravity, or unexpected folds and creases created by excess fabric that was not tailored or fixed. Scale: Thinking through slices in terms of scale offered interpretive inter-scaler design inquiry at multiple levels: inhabitable forms; relationship to bodily datum; modular unit, component, and assembly design; possible size and shape of final artifact. Scaling of slices represented as 2D drawings permitted the most diverse variations before selecting slices to re-considered at other scales, and whether as solids, surfaces or spatial conditions. Transformation: Examination and investigation of slices with desirable morphologies could be re-connected in the virtual model, and operations offered controlled exploration with the ability to adjust relationships between sections using variable paths of travel. Formwork Re-design: Extracted 2D spatial data from 3D cast forms as an analysis of formwork design showed deviation of material from original formal intent otherwise difficult to assess visually. This allowed for the re-design of formwork to consider and reflect new scale, edit out undesirable parts of cast forms as a result from excessive fabric and material, and achieve more rigorous control of surface formation. It also permitted opportunities to reconfigure the fabric within a single formwork apparatus to yield variable forms of incremental change.

5. Analysis and Conclusions

5.2. Summary of Results

5.1. Summary of Observations in Process

By nature, solid cast forms are objects where sectional qualities are difficult to visualize. In formwork that is designed to be adjustable, variability can be noted most importantly in the sectional experience of the cast forms. Working in reverse from 3D forms to 2D orthographic projections by way of 3D scanning the cast prototypes, tomographic visualization offered insight for both compelling and undesirable deformations in the surfaces and allowed nuanced variations to be tracked and reworked through more controlled parameters in formwork re-design, while scalar considerations suggested what the full-scale work could become.

The various steps in the design process revealed observations about material and form that reinforce the impact of studying inter-scalar tomographies. Cast: Small scale plaster casts using flexible formwork served as quick studies of variable sectional forms and surfaces. When loaded with weight of the material, the fabric responded with its own contour, allowing formal qualities to emerge. Scan and Virtual Model: Visualization of the original physical cast as a virtual model and mesh invited imagination of spatial interpretations, allowing the possibilities of form to be explored in terms of solid, surface, and volume, as well as orientation in space to be considered. Slice: Two-dimensional tomographic representations taken in multiple axes showed irregular variation and allowed for visualization of the dynamic morphogenesis of surface within the overall cast form. From this set of

Since these actual cast models are solid objects, cutting them with physical tools would alter the model into fixed forms of the same scale, whereas slicing the virtual model allowed the cutting plane to be shifted and multiple sections extracted in several directions, at the same time transforming the viewing plane. Exploring an integrated analog-digital interface in form finding, rather than seeking resolution of form in either the actual or virtual model created a feedback loop that acts as design

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Inter-scalar Tomography in Variable Formwork

agency for the creative process derived from an interplay and interpretation of solid, surface and space that decodes the possibilities of the gestural model at other scales. Advantages working between two modalities lies in the analysis of morphogenesis from physical data in the making processes, rather than strict optimization or rationalization of form in the digital realm. Ultimately, to justify the material behavior of the plaster or concrete, it is critical to comprehend how the formwork was designed for variability to occur, and how it allowed for possible ways the material would choose to react that makes us think about “matter as possessing morphogenetic powers of its own,” (DeLanda, 2015), as well as noting the difference between measurable parameters and qualitative surface formations.

6. Further Work This work is currently being developed through 1:1 scale prototyping in fabric formed concrete and the design of variable formwork for the application of modular assemblies informed by material systems where form and surface are integrated as spatial experiences. This research expands upon hybrid analog-digital teaching methodologies in design and communication that can be further explored as large-scale prototypes for design in architecture, landscape architecture, industrial and product, as well as fabrication technologies. The underexplored potential of 3D scanning as design tool can be applied to design-build approaches and projects in the field as well as off-site fabrication research.

7. Acknowledgements The work presented in this paper was developed for and began as initial testing of fabric formwork and variable formwork design towards a design-build project entitled, “Inhabiting Surface”, supported by a departmental grant from NYIT’s School of Architecture. “Inhabiting Surface” is a collaborative project with Cal Poly Pomona Department of Landscape Architecture Assistant Professor Rennie Tang to create a playscape for iPoly High School.

http://ecaade.org/downloads/ecaade2017_volume2 _screen.pdf. Chandler, A. (2017). Concrete as Equipment. In A. Chandler and R. Pedreschi (eds.), Fabric Formwork. London: RIBA Publishing. DeLanda, M. (2015). The New Materiality. Architectural Design, 85.16-21. doi:10.1002/ad.1948 Marcus, A. (2014). Modular Variations. Design Agency, ACADIA 2014, 19-22. Menges, A. (2015). Fusing the Computational and the Physical: Towards a Novel Material Culture. Architectural Design, vol. 85,5, 8-15. https://doi.org/10.1002/ad.1947 Pallasmaa, J. (2009). The Thinking Hand: Existential and Embodied Wisdom in Architecture, Chicester, U.K: Wiley. Prousalidou, E. (2012). A Digital Model for Fabric Formwork Panels: Using physical data to train the digital model. In Digital Applications in Construction Vol.2, eCAADe 30, 149-157. Retrieved from http://papers.cumincad.org/cgibin/works/paper/ecaade2012_209. Sheldon, D.R., (2002). Digital Surface Representation and the Constructability of Gehry’s Architecture (Doctoral Dissertation) Retrieved from MIT DSpace, (http://hdl.handle.net/1721.1/16899). Kwintor, S. (2002). Architectures of Time: Toward a Theory of the Event in Modernist Culture. USA: The MIT Press, pp.1-32. West, M. Araya, R. (2009). Fabric Formwork for Concrete Structures and Architecture. In B. Kröplin and E. Oñate (Eds.), International Conference on Textile Composites and Inflatable Structures. Barcelona: CIMNE.

8. References Becker, M. (2014). Configurations of Intensity. Design Agency, ACADIA 2014, 589-596. Chaltiel, S., Bravo, M., Chronis, A. (2017). Digital fabrication with Virtual and Augmented Reality for Monolithic Shells. In Sharing of Computational Knowledge! Vol. 2. Retrieved from

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