(Re-)Constructing, Segmenting, Bending, Coating – On Moments of Affordance and Persistence in an Aluminium Alloy Manufacturing Process
Introduction
Meandering anywhere between timeless and toxic, progressive and technoid, impeccable and non-degradable, there are probably very few material histories so young and yet so full of divergent symbolism than those of the most abundant metal in our earth crust.1 While utmost optimism surrounded its 19th century industrial introduction, suggesting that after stone and steel ages, “indications now point to the next being an age for aluminium and its alloys”,2 it appears, at least from an engineering point of view, still today as a rather novel and open material, used at times with hesitance, at others with enthusiasm in structural applications.
Advantages of the material being lightweight, efficient and non-corrosive contrast with its complex metallurgical characteristics, structural inferiorities to steel as well as stress-strain curves making its behaviour more difficult to predict.3 Playing on these material controversies and determinations, the present paper unfolds an aluminium alloy manufacturing workflow in an interplay of potentials and constraints arising thereof. As it discusses the computational manufacturing of the piece einander by German artist Albert Weis, it suggests how innovation emerges in the development of a workflow oscillating between digital technologies and craft techniques and foregrounds ambiguities of persistence and process along this way.
The argument begins from more recent understandings of ontologies and their strengthened links to time-related matters of becoming in order to approach potentially formative and cross-medial properties of operations. Using American psychologist James J. Gibson’s concept of “affordance” as a catalyst, it delineates an alternative approach to computational modelling and manufacturing, which embraces the formative and inspirational potentials of both positive and negative forms of such determinations. As a speculative scenario, the resulting workflow may turn into a somewhat tentative yet illustrative example of what instigates when discourses on digital manufacturing are shifted from prevalent fixations on their possibility to constraint spaces.
From Ontologies to Affordances
When the anthropologists and sociologists Javier Lezaun and Steve Woolgar introduced their 2013 Social Studies of Science issue, they put their insecurities where to take the ontological turn in question marks: Asking “What should we make of, and with, this renewed interest in matters of ontology?“,4 they reviewed and responded to growing interests and productivities of the term in discourses in the field of Science and Technology (STS) – not least drawing back to Andrew Pickering, who ever since his Mangle of Practice had demanded „an ontology of decentred becoming.“5 Foregrounding motives of process and productivity, such ontological understandings stress questions of action, multiplicity and time as opposed to traditional, more static understandings of the concept.
In a 2017 issue on Operative Ontologies and the following conference “Schalten and Walten” (the switching of circuits and ruling), held at the Internationales Kolleg für Kulturtechnikforschung und Medienphilosophie (IKKM) in Weimar in 2019, those matters of how things are brought into existence were put at centre stage by media theorists Bernhard Siegert and Lorenz Engell. The present inquiry reinforces their question into “how manifold ontological operations result in various forms of being, but also in becoming”,6 as it shifts the focus towards time-based matters of realisation, as well as the workflows, instruments and media linked herewith. With special regard to this operative dimension of ontologies, it follows an understanding where virtual and physical, informational and material actions are inherently interwoven and linked:
“To inquire ‘operative ontologies’ means to inquire the tangible ontic operations, which constitute ontological differentiations in the first place – among others, those of form and matter or representation and represented, thing and process, figure and canvas, active and passive, message and medium, subject and object, human and animal, etc.. Exactly these ontic operations stand at the core of what is commonly referred to as cultural techniques.”7
In his introduction to the concept, Siegert frames how operative ontologies only become productive through the cultural techniques of their realization. Before an understanding of this inherent link then, researchers and practitioners need to accommodate for such operative dimensions, and realise how it is impossible to perceive, study and develop their work without looking on the operations in which its is put into practice.8 Applied to the present case, this would mean to neither understand the digital model without its underlying methods of digitizing, re-informing and projecting, nor the physical artefact without the manifold processes and workflows inscribed in it. All the more, since the often evoked confluence of the analogue and the digital maybe first and foremost becomes evident through epistemic practices of these realizations: from filtering to cutting and scaling to reflecting.9
How to inquire into such operative dimensions of ontologies within the realm of computational manufacturing? Several previous explorations in the field have shown prospects of working at the interstices of design and making as a manifold and process-based engagement in bespoke, both digital and craft workflows.10 Before this background, the given paper proposes to apply the concept of ‘affordance’, to be conceived as the offerings throughout operations and processes of realisations and their imprint on the results of these very realisations. Art theorist Ann-Sophie Lehmann has recently argued how approaching artworks as indexes of their constitutive processes may help to augment fixations on static concepts of author and artwork, discussing fingerprints between soft, hard and digital surfaces as well as oil as a mediating agent in artistic working processes across history11 – interestingly even naming examples from the realms of software and design to approach her matters of interest:
“It appears, from a material point of view, that substantial analogies between oil, wax, glass, plastics and even computer graphics become obvious. All of them are (semi-)transparent and polymorphous, ‘afford’ realism and foster the de-materialization their generated artefacts.”
The concept of ‘affordance’ refers back to the American psychologist James J. Gibson and his fundamental work on The ecological approach to visual perception. Here, Gibson sets out to analyse the human environment through three notions: medium, substances and surfaces. His prime example for a medium is air, which is what we need to breathe, shout and smell; for a substance it is water, which we may neither use to breathe, shout or smell, but eventually to swim or pour concrete; the surface, again, is the water pane, which separate the two others. This makes surfaces crucial to Gibson, because they resist, reflect, shape what comes through them (fig. 1), in other words: they filter their outcome. But “[w]hy, in the triad of medium, substances, and surfaces, are surfaces so important? The surface is where most of the action is.”12 It is there, where things are absorbed, reflected, distorted, touched, diffused, vaporized, transmitted; simply put: where actions and reactions take place. But what are surfaces of computational manufacturing, and how do they resist, reflect and shape those actions taking place across its interfaces, materials and processes? Or to speak with Gibson: “how do we go from surfaces to affordances?’13

Figure 1: “The characteristic textures of the surfaces of various substances” in Gibson’s The Ecological Approach to Visual Perception [1979] (1986).
Affordances refer to offerings made by materials, tools or processes, and can be conceived as suggestions on how to employ and direct them towards a result. Along her mentioned contributions, Lehmann argued for the concept’s importance for ANT and its reception in the first place, quoting Latour’s own referral to Gibson as he saw that “things might authorize, allow, afford, encourage, permit, suggest, influence, block, render possible, forbid, and so on”.14 While the art theoretician considers this opening prospects to amend and revert anthropocentric theories of action and creativity, it appears that also in the realms of design and engineering, affordances have in fact proven to be a very useful tool – showing trajectories to follow both human and non-human agencies across moments of interaction and collaboration, such as in robotics and human-machine interaction.15
At the same time, however, it appears equally important to ask for moments of absence or inversion of positive affordances (sometimes referred to as negative affordance or constraint), and the whys and hows that they may be just as productive as their presence in the first place. With regard to computational design and manufacture, this also formulates a counterpoint to present perspectives on notation as mere limitation or bottleneck, which often raise hopes for immediate, liberating prospects of technological advance against “the divisions of labour – and the constraints of symbolic representation of the production drawing – that characterise the modern industry. The fast-moving front edge of the flock is an exciting place to be.”16 Bird flocks have no single leaderships, however, which is maybe why swarm behaviour, the manifold rules and actions of separating, aligning and attracting, becomes the actually fascinating field of study. Applied to our case: it is maybe not so much about leaving all constraints and ruptures in ‘digital chains’ behind, but rather about focusing precisely on their constitutive potentials, which could form a promising and complementary perspective.
The notion of ‘affordances’, in that respect, may reveal more thorough understandings of the specific structures, hierarchies and logics which are inscribed along computational design and manufacturing processes. With respect to the given workflow, this may reveal how both positive and negative affordances do emerge and take effect between the substances and surfaces. This is not to say that these affordances could not have been (sometimes more, sometimes less) easily be by-passed through different setups and workflows – involving, among others, alternative avenues to matters of cost, time or availability. On the contrary, this may be an argument how consciously stepping back from such ‘optimisations’ and rather embracing them as necessary contributors to the process, that those specific possibilities and boundary conditions become active agents guiding and shaping the project outcome.
Fostering Persistence in Manufacturing Processes
Affordances are not static. Also, they do not only affect and effect processes at a single point in time. Rather, they are themselves taking part in complex practices of their own constitution, appropriation and alteration. Theoretically, this is linked to Siegert’s understanding that operative ontologies only exist through and with the cultural techniques linked to the actions of their emergence.17 Practically, however, bearing in mind such dynamic understandings of affordances holds certain relevance for a successful application of the concept. It brings into focus how they are nothing which exists a priori, but only in and through fluid and changing processes of their emergence and exercise.
As the given project inquires affordances in modelling and building processes, various related cultural techniques of simulating and manufacturing gain importance: recursive relations and realisations of, among others, drafting, prototyping, probing, verifying, collapsing, marking. The underlying working environments (that is: Gibson’s surfaces), the machineries, software, interfaces and tools, are therefore not only to be understood as a medium to represent something a posteriori, but as a speculative instrument for generating knowledge in the first place. Notably, such attention for constitutive and process-related capacities builds upon the concept of the ‘persistent model’ as it was previously proposed by Phil Ayres:
“The focus is turned from the design of the specific artefact to defining relationships between design drivers that possibly change overtime. These changes are absorbed into the design and are expressed in particular quantitative and qualitative attributes of the resultant instance. (…) The novelty in the notion of the persistent model lies in its persistence beyond the making of the modelled. The circularity inherent in the design process does not end when the artefact is made. The persistent model permits the potential expression of variety over time by keeping circularity open after the synthesis of the artefact.”18
In doing so, this approach experiments with prevalent dependencies of modelling and manufacturing. This refers to logics where the model (that is, the virtual or physical simulation or representation) would conventionally only appear as some preliminary sort of draft, only subordinate to its later realization on site (that is, that which is built). The given project alters, plays and ultimately inverts these logics. In order to approach a more symbiotic convergence of structure and model, it experiments with a rather hybrid system of exchange between, among others, 3D simulation, CNC-driven bending, water jet cutting and laser scanning. Apart from building upon prior convergences of the virtual model and its physical execution by the author, it takes inspiration from broader explorations of the concept at CITA – which experimented with workflows which are persistent in that they intertwine digital and physical manipulation, virtual simulation and spatial intervention in order to mediate knowledge from diverse domains such as material sciences, traditional craftsmanship and computational manufacturing into design.19
The following tentative study will approach how both human and non-human translations of (re-)constructing, segmenting, bending and covering become constitutive for the given process. Looking on two exemplary pairs of specific operations and the ontologies linked with their exercise, it discusses the modelling and fabrication of the piece einander by German artist Albert Weis under the present conceptual and methodological frameworks. As a contribution to the newly build Portalklinik to the Ludwig-Maximilians-University Hospital Munich, the design frames an exterior courtyard between old and new building stock with two large ellipsoid shapes in bright gold and gold, interweaving and touching each other at two points. After passing the competition phase, the contribution which was represented in schematic plans and a working model had to be planned further towards production. Specifically, this meant to develop and execute a planning and manufacturing workflow with a North German manufacturer, the final pipe geometry measuring somewhat 1150 x 850 centimetres from extruded and anodised aluminium pipes.
Geometry: (Re-)Constructing and Segmenting
In terms of geometry, ellipsoids are rather easy to describe: as plane closed curves with two focal points, each point of an ellipse shares the same, constant added distance connecting it to these two points. While every school child will learn about hands-on methods of its construction with strings and nails, this and other historical methods have, without question, influenced large parts of its architectural appropriations and approximations, from arches, over squares to floor plans (fig. 2). What these methods to handle its strikingly simple forms reveal as well, however, is that ellipsoids approximate between their maximum and minimum radii, resulting in an infinite number of mediating steps, and therefore in fact permanently changing radii. This not only accounts for their aesthetic impression as ‘simple’, continuous and somewhat timeless curvatures. At least from a manufacturer’s point of view, this also, still today, turns them into a rather complex ‘free-form’, in the sense of a geometry which cannot easily be broken down into static parameters which would remain fixed over the development of the geometry.
Figure 2: Historical employment of string methods and arc segmentation to construct surbased arches in Ambroise Bachot’s Le Gouvernail (1598) and Lorenzo San Nicolás’ Arte y uso de architectura (1639), cited after: Huerta, Santiago. “Oval Domes: History, Geometry and Mechanics.” Nexus Network Journal 9 (2007), 234.
For those and other reasons, research in varying forms of geometric approximations of ellipsoids is still an ongoing endeavour, with mathematician Paul L. Rosin giving a somewhat less recent yet illustrative comparison of several variants.20 With equal interest in matters of description, logistics and assembly, the original ellipsoid geometries of the given design had to be segmented into a number of elements each, taking two major affordances into account: with the chosen CNC assisted bending machine for pipes of this rather large diameter (the surface towards the material, if you will) only single radius geometries could be produced. At the same time, any anodisation workflow, which protects the aluminium alloy from external influences such as weathering and corrosion, is usually restricted in length due to the dye baths used throughout the process. In this special case of non-linear elements, maximum segments lengths of 4500 millimetres were possible. At the same time, any chosen form of segmentation had to preserve the overall ellipsoid curvature and avoid any obvious bumps or changes of direction.
As an answer to these affordances and after several tests balancing fidelity and costs with artist and manufacturer, the reconstruction of the two 3/4 (or 6/8) ellipsoid fragments through six piecewise circular arcs was chosen to approximate the original geometries (fig. 3). While keeping continuous segment lengths, their distribution answers to the 26° rotation in z-axis, covering the ‘top’ areas of lowest inclination around the minimum radius with one segment (A3, B3) and distributing the remaining 5 at both sides. Applying a redesigned variant to what Rosin referred to as the French-method (that is, one with equal segment lengths, as requested by the artist), each transition point between two arcs (the later joints between the segments), was reconstructed with shared tangent lines, that is with the starting and end radius lying on one line towards their respective centres. In other words, the normals of all arcs are identical at each intersection of two arc segments, as they share a common tangent. What one can read out of the communication protocol is how these guidelines of the geometry are then reported between CNC operator, planner and machine, the red dashed line showing the overlay and fitting of respective radius which only changes its length.

Figure 3: CNC bending data of manufacturing model, showing the arc segmentation of both elipsoids, einander byAlbert Weis, planning protocol by Büro Vogel Bauer, 2020.
The resulting model serves as a feedback loop between the physical and virtual instalment of the geometry, as it feeds back information from the actual machines assisting in the manufacturing workflow. Obviously producing deviations from the initial geometry through the given process of approximation, this resulting manufacturing model had not only to meet artistic aspirations, but also be tested against conflicts with requirements from structural engineering and detailing, which were both conducted originally with ellipsoid construction lines – notably, the required distance range between both pipes for joining as part of the engineering protocol, the respective detailing for these joints as well as the fact that joints would not lie on the original ellispoids.
Before approval, another round of tests in the modelling environment verified that all boundary conditions (apx. 11 mm A2/B2 and 19 mm A5/B5) could be kept, so that the model then served as input data for the CNC-assisted bending process of all segments. After a test assembly of the structure in February 2021 in the manufacturer’s workshop, these positions were then again measured against the original 3D model. Therefore, laser reference points were measured and verified against the corresponding distances in the parallel 3D model (fig. 4). Again re-checking and -adapting the built geometry against its model, bespoke adaptions of the two connector plates could be incorporated and fabricated. While one could refer to various other comparable moments across the production chain – such as the adjustment of cross profiled, base connectors (fig. 5) or alterations due to coordination with landscape planning and drainage requirements – such first balancing of physical and digital influences already points to the larger image, which is what has been referred to a persistent modelling process.

Figure 4: Test assembly and laser scanning against 3D simulation in the workshop, 2021.

Figure 5: Cross-profiled base connectors, waterjet cut stainless steel, 2021.
Fingerprints: Bending and Coating
Extruded aluminium alloy tubes (ENAW6063 T66) with dimensions d=200mm and t=10mm were used for each segment of the structure. At the border of the dimensions which were possible in this CNC assisted workflow of the chosen manufacturer, bending tubes of this diameter will show traces of production, since heavy forces are needed to bring the pipe into the narrow curvature defined with the numerical input data. With aluminium like most other metal materials, it is relatively unproblematic to erase such traces of the process, to smoothen and polish them out towards one pristine surface, so that a segmented geometry would resemble a single piece – one very powerful example being the piece Wirbelwerk by Olafur Eliassonas a permanent installation at Lenbachhaus Munich, which is assembled from a large number of individual segments with changing radius and thickness, but then smoothened to one continuously changing shape, deliberately not showing this assembly in the final artefact.
Also within the present workflow, this was obviously an option. After the fabricator had even prepared polished and unpolished specimens (fig. 6), however, the opposite strategy was chosen, not erasing these traces from the material surface, but leaving them to last on the structure. As fingerprints of the applied bending machinery, they persistently tell about this constitutive process to the viewer. While this evidently also helped to reduce costs of the project, it added conceptual ambiguity and afforded interesting contrasts to the soft skin of the following gold and bright gold anodisation.

Figure 6: Material specimens of polished and unpolished aluminium alloy pipes, 2021.
At the same time this may also be understood as a reinterpretation of such actions of covering in the first place: those forms of coating are in general, and anodisation processes in specific, applied in order to protect the material from influences of use, time and weather. Now it is precisely such signs of process, however, which are persistently protected under the covering skin, preserving their traces even from following processes of weathering and corroding which would make them less and less readable over time. Pressing themselves through their covering skins, they will continue to tell about their constitutive processes (fig. 7). Therefore, instead of masking out and befogging the respective manufacturing workflow, not only an avoiding but an affirmative strategy is chosen quite consciously: one which does not only leave its imprints and traces on the final artefact, but uses them to add something to its narrative; or to quote Lehmann, one which shows that „[f]ingerprints, it appears, are well suited to create new and unexpected relations between soft, hard, and digital surfaces.“21

Figure 7: Material specimen of unpolished and anodised aluminium alloy pipes, 2021.
When the pipes arrived for assembly on site then (fig. 8), many affordances, both positive and negative, had inscribed themselves into the process and its oscillation between cultural techniques of modelling and manufacturing. What remains visible, among others, are the traces of the chosen geometric reconstruction, the segmentation workflow as well as the traces of the powers of bending and their protection for further interpretation. Interestingly enough, a highly standardized yet soft building material such as aluminium is not reified in its pristine and impeccable surfaces, but persistently bears and protects the marks of its fabrication as a memory of the very processes driving its constitution.

Figure 8: Mounting of the structure at the Portalklinik to the Ludwig-Maximilians-University Hospital Munich, 2021.
Conclusion
In an exemplary attempt to approach an aluminium alloy-based modelling and manufacturing workflow from its both operative and ontological founding, the present approach proposed moments of persistence and affordance as possible catalysts. Exposing the concept of operative ontologies to an experimental, practical setting, this not only required to track and chase how multiple ontologies (among others, material, software and machinery) coexist and converge with and through the operations and actions they are involved in. It also means to follow an increasingly diversified and complex variety of human and material actors and agencies. Looking on exemplary operations of (re-)constructing, segmenting, bending and coating through Gibson has shown how it is precisely in this place somewhere between surfaces and materials “where most of the action is.”22
Being nothing but a first, tentative inquiry into these matters, this may still illustrate some prospects of conceiving the artefacts of computational manufacturing not only as a manifestation of and endless and ever-growing range of possibilities, but also (or in fact much rather) read them through the manifold constraints along their processes. It also means not to look backwards on the final artefact, but rather strengthen persistent matters of time and action at all stages of its creation. In fact, such perspectives on interactions and inscriptions between materialitiy and manufacturing data may reveal more about their hybrid characteristics, which may be at once soft and hard, static and dynamic. It may also reveal how they speak on their production processes, among others, their traces, boundary conditions and margins of tolerance, just like any other means of production had before. Measuring out the wiggle room of these processes therefore not only helps to put prevalent notions of the ‘digital chain’ into perspective. It also shows how the affordances of computational technologies prevail, which may help designers in shaping the outcome of their processes more persistently.
In an interplay of surfaces and substances, of instruments and materials over time, affordances emerge and inscribe themselves into an artefact like einander, meant to last and outlast all following human and non-human influences. Drawing on Andrew Pickering again, one may argue how such affordances create what he frames as ‘islands of stability’23 within otherwise largely open and unscripted workflows. Eventually, those islands between our restrictions, constraints and boundary conditions, may be just those guideposts which persist, even though they are viewed as either tragically lost or fully left behind by techno-romanticists and -positivists, respectively.
Acknowledgments
The author thanks Studio Albert Weis, the structural engineer Rüdiger Jockwer as well as the manufacturer Metallbau Wittenberg for their cooperation and dedication in realising the project. He further acknowledges for the support of the Department of Digital and Experimental Design at the Berlin University of the Arts, as well as of the Cluster of Excellence “Matters of Activity: Image Space Material” funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy – EXC 2025 – 390648296.
Contact
Frank Bauer M.A., M.A.
Pre-Doctoral Researcher
Matters of Activity. Image Space Material
Cluster of Excellence
Humboldt-Universität zu Berlin
Unter den Linden 6, D-10099 Berlin
Phone: +49 176 44432957
E-Mail: frank.bauer@hu-berlin.de
- Cf. Schatzberg, Eric, “Symbolic Culture and Technological Change: The Cultural History of Aluminum as an Industrial Material,” Enterprise and Society 4, no. 2 (2003): 233-36. [↩]
- Cited after: Maier, Helmut, “’New Age Metal’ or ‘Ersatz’? Technological Uncertainties and Ideological Implications of Aluminium up to the 1930s,” Icon 3 (1997): 181. [↩]
- Cf. Gitter, Reinhold, “Aluminium Materials for Structural Engineering – Essential Properties and Selection of Materials,” Structural Engineering International Volume 16, no. 4 (2006): 294-300. [↩]
- Lezaun, Javier, and Woolgar, Steve, “The wrong bin bag: A turn to ontology in science and technology studies?,” Social Studies of Science 43 ( (2013): 321. [↩]
- Pickering, Andrew, “The Ontological Turn: Taking Different Worlds Seriously,” Social Analysis 61, no. 2 (2017): 145. [↩]
- Engell, Lorenz, and Siegert, Bernhard, “Editorial,” Zeitschrift für Medien- und Kulturforschung 8, no. 2 (2017): 6. [↩]
- Siegert, Bernhard, “Öffnen, Schließen, Zerstreuen, Verdichten. Die operativen Ontologien der Kulturtechnik,” Zeitschrift für Medien- und Kulturforschung 8, no. 2 (2017): 99. [↩]
- Engell, Lorenz, and Siegert, Bernhard, “Editorial,” Zeitschrift für Medien- und Kulturforschung (1) (2010), 7. [↩]
- Siegert refers to the annual IKKM topics (Framing/Sewing, Appearing/Disappearing, Condensing/Dispersing, Showing/Causing, Reproducing/Replicating and Turning back/(Self-)Reflecting) in their relations of analogue and digital practices. More recently, such interest reappeared related to the current emphasis on such elementary, epistemic practices of Weaving, Filtering, and Cutting which are installed and investigated at the Cluster of Excellence Matters of Activity throughout its project frameworks. [↩]
- Cf. Sheil, Bob, “From making the bespoke to manufacturing the bespoke,” in Manufacturing the Bespoke: Making and Prototyping Architecture, ed. Bob Sheil (London: Wiley & Sons, 2012), 14-27. [↩]
- Cf. Lehmann, Ann-Sophie, “Taking Fingerprints The Indexical Affordances of Artworks’ Material Surfaces,” in Spur der Arbeit. Oberfläche und Werkrprozess, ed. Magdalena Bushart and Henrike Haug (Köln: Böhlau, 2018), 199-28; Lehmann, Ann-Sophie, “Das Medium als Mediator. Eine Materialtheorie für (Öl-)Bilder,” Zeitschrift für Ästhetik und Allgemeine Kunstwissenschaft 57, no 1 (2012): 69-88, here especially 82-85. [↩]
- Gibson, James J., The Ecological Approach to Visual Perception (New York: Taylor & Francis, [1979] 1986), 25. [↩]
- Ibid., 127. [↩]
- Latour, Bruno, “On the Difficulty of Being an ANT – An Interlude in the Form of a Dialog,” in Reassembling the Social – An Introduction to Actor-Network-Theory, ed. Bruno Latour (Oxford: Oxford University Press, 2005), 72. [↩]
- One of the various applications for Gibson’s concept in the field of artificial intelligence and biomorphism exemplifies ecological optics for enacting perception-action synergies – robots being able to conceive things as to be picked up or a stone on the ground as something to be tripped over, for instance. Cf. Horton, Thomas, Chakraborty, Arpan and St. Amant, Robert, “Affordances for robots: A brief survey” Avant 3 (2012): 70-84. [↩]
- Penn, Alan, “Foreword,” in Fabricate: Making Digital Architecture, ed. Bob Sheil and Ruari Glynn (London: UCL Press, 2011), 12. [↩]
- Siegert, “Öffnen, Schließen, Zerstreuen, Verdichten”, 101. [↩]
- Ayres, Phil, “The origin of modelling,” Kybernetes 36, no. 9 (2007): 1234-1235. [↩]
- Bauer, Frank and Skafte, Lasse, “Persistent Modelling of the Built,” in Design Commons: Practices, Processes and Crossovers, ed, Gerhard Bruyns and Stavros Kousoulas (Berlin: Springer, 2021, in print). Under the lead of the research group Center for Information Technology and Architecture (CITA) at The Royal Danish Academy Copenhagen promotes an understanding of practice-based architectural research openly merging digital and physical processes. Cf. Ramsgaard Thomsen, Mette, and Tamke, Martin. “Prototyping Practice: Merging Digital and Physical Enquiries, ” in Rethink! Prototyping, ed. Christoph Gengnagel, Emilia Nagy and Rainer Stark (Cham: Springer, 2016), 49-62. [↩]
- Cf. Rosin, Paul A., “Survey and comparison of traditional piecewise circular approximations to the ellipse,” Computer Aided Geometric Design 16, no. 4 (1999): 269-286. [↩]
- Lehmann, “Taking Fingerprints”, 201. [↩]
- Gibson, The Ecological Approach, 127. [↩]
- Cf. Pickering, Andrew, “In Our Place. Performance, Dualism, and Islands of Stability.” Common Knowledge 23, no. 3 (2017), 381-395. [↩]

