Theories and Models of Parametric Thinking

Rivka Oxman1, Ning Gu2 1Technion Israel Institute of Technology 2The University of Newcastle [email protected] [email protected]

Due to significant recent design-related technological developments, design theories and processes are undergoing re-formulation and an epistemological shift. The tools and practices of parametric design are beginning to impact new forms of Parametric (PDT). The present work is motivated by the need to explore and formulate the body of theoretical concepts of parametric design. It is built around the intersection of three areas of knowledge: cognitive models of design, digital models of design, and parametric tools and scripts. The work identifies forms of cognitive mechanisms in parametric design; types of logical flow of information that can be applied in digital processes for performance-based design; and form finding. It explores the impact of parametric models and tools upon styles of design thinking from conception to production. These are presented as a body of knowledge in the search for thinking and process models of PDT in design.

Keywords: Parametric Design, Parametric Schema, Parametric Design Thinking, Generative Design, Performative Design

INTRODUCTION sign methodology and new epistemological bases of Due to significant recent design-related technologi- resulting in new forms of design cal developments, design theories and processes are thinking (Oxman and Oxman 2014). We refer to these undergoing re-formulation and an epistemological emerging phenomena as Parametric Design Think- shift. Parametric design systems today can adapt ing (PDT). to changing context (Woodbury 2010) under the in- The work presented in this paper is motivated by fluence of parametric languages and scripting tech- the need to explore and characterize current theories niques (Jabi 2013) and to diverse topological rela- and practices of parametric design and to reformu- tionships and generative processes of design (Ox- late the underlying concepts behind parametric de- man 2006). Among its forms of influence paramet- sign thinking. One of the bases for understanding ric design has affected the topological and formal these phenomena is the emergence of a body of cog- characteristics of produced in diverse design nitive and computational concepts that are expand- fields such as , and fash- ing the role and overall design impact of paramet- ion design. Current research has also shown that ric design. This body of concepts is rapidly becom- the development of new tools and scripting envi- ing the nexus of theory and production in paramet- ronments are also contributing to a distinctive de- ric design. Terms and concepts such as parametric

Generative Design - Concepts - Volume 2 - eCAADe 33 | 477 schema, algorithmic thinking and parametric reason- tween pure parametric tool manipulation and the ing are becoming an important body of new knowl- utilization of a broad understanding of architectural edge in the search for a general theory of PDT. knowledge in the parametric design process. For ex- Following upon recent studies on parametric de- ample, some who embrace what is referred sign methods and tools in academia and practice to as may tend to abandon fundamen- (Hernandez 2006; Iordanova 2009; Cellini and Vaz tal architectural principles and concerns, having the 2012) we focuses in this research upon theoretical tendency to avoid comprehensive critical judgment and methodological issues, and the definition of con- and aim instead for formal novelty through comput- cepts while exploring their relationships in order to ing power without addressing other basics of archi- expand current and knowledge. tectural design such as social, historical and environ- Our research is built around three areas of knowl- mental concerns, functional and programmatic re- edge: cognitive models of design, digital models of quirements, and user's psychological needs (Castel- design, and the examination of the impact of para- lano, 2011). metric tools and scripts. The research aims to explore The following three points are generally charac- their relationships and their mutual impact on PDT. In teristic of the parametric design process: the following sections a body of design topics is intro- • Designers design rules and define their logi- duced, discussed and presented with specific exam- cal relationships in the creation of 3D visual- ples from architectural design. ization models PARAMETRIC DESIGN The distinction of parametric design in comparison Parametric design thinking can be defined as hav- to traditional computer modeling is that rule-sets ing three characteristics - thinking with abstraction; become basic design procedures in configuring 3D thinking mathematically; and thinking algorithmi- models of parametric design (Abdelsalam, 2009). In cally (Woodbury, 2010). Thinking with abstraction is building parametric models, designers set variables a base that enables parametric design as a genera- and digital data flows, adjusting the values of param- tive approach for producing parallel alternatives and eters, and revising the rules accordingly. Rather than it also enables parts of the parametric model to be traditional configuration ways of the object itself, the reused. Thinking mathematically refers to the the- design of the generative rule set and their logical rela- orems and constructions used to define the script- tionships is becoming the main focus of design think- ing language for design representation and genera- ing. In this way, more alternative solutions can be ex- tion. Thinking algorithmically means that the script- plored by changing the parameters of the logical re- ing language provides functions that can add, repeat, lationships (Hernandez, 2006; Karle & Kelly, 2011). modify or remove parts in a parametric design. A recent cognitive design study (Yu et al, 2014) Woodbury claims that in a parametric design en- presents the following findings: Designers write their vironment designers need a different kind of knowl- rules referring mainly to geometric modeling focus- edge that can "predict persistent effects to under- ing on geometric elements. This suggests that wider stand the diversity and structure of the mathemat- comprehensive aspects of architectural knowledge, ical toolbox, and to shuttle between the intended principles and concepts are outside of this primary effect and mathematical invention that models it" focus. (Woodbury 2010). That means that parametrically • Designers can change and modify their de- discriminating designers would need to know more sign at any stage than merely basic architectural knowledge. How- ever, there should also be an informed balance be-

478 | eCAADe 33 - Generative Design - Concepts - Volume 2 Designers can change and modify their own rule- can be formulated and represented as generic para- based representations in any stage of the design pro- metric schema. The adoption of design patterns in cess. In processes of parametric design, the design certain domains is a phenomenon that has been ob- system is differentiated and correlated. In the para- served by a number of researchers in both traditional metric model, all design procedures and activities architectural design (Alexander et al., 1977) and in are related to one another and clearly defined (Schu- parametric design (Woodbury et al., 2007). macher, 2008). Therefore, designers can return back According to Brett Steele, parametric design in any stage and revise parameters or rules to mod- knowledge is a model of design thinking that in- ify their design or to pursue a different one. This al- tegrates topological patterns within generic typolo- lows them methodologically to keep the design pro- gies. This cognitive capability has been termed, the cess open and flexible. "serial sensibility" (Brett Steele, in Lee and Jacoby, 2007). • Design alternatives can be developed in par- allel in any stage The Role of the Cognitive Parametric Schema Designers often consider a relatively limited number The cognitive role and the logic of a generic knowl- of alternative solutions (Woodbury & Burrow, 2006). edge schema as a basis for understanding pro- In the parametric design process, once the rules are cess of schema adaptation and refinement by re- implemented, unlimited numbers of design alterna- representation can be demonstrated through exam- tives can be generated in parallel. The possibility ples of prior research (Oxman, 1992; 1997). The emer- to use parallel design generation is changing modes gence of a new schema is a fundamental cognitive of thinking and contributes to explorative processes capability of creativity in the human . In the (Hernandez, 2006; Holland, 2011; Karle & Kelly, 2011). process of design, , and construction the schema can be modified and adapted. To summarize, PARAMETRIC DESIGN THINKING (PDT) the role of the parametric schema: Beyond any particular formal style or , parametric design thinking is emerging as a theoret- • Providing an explorative mechanism ical topic (Oxman and Gu, 2013) and a key model • Providing a medium for generating variation of digital design. With the emergence of new lan- • Providing a medium for transformational pro- guages and tools, and in comparison to traditional cesses models of the parametric, the generic formulation of a Parametric Design Schema should be formulated The cognitive roles and the logic of a generic schema and explored as a comprehensive theoretical frame- (referring in this case to architectural knowledge of work to support design. basic classical temple types) can be demonstrated Karle & Kelly, 2011 describe this process as "a new through the example of the Classical Greek Temple, way of relating tangible and intangible systems into reflecting the different styles, geometrical series and a design proposal removed from digital tool speci- proportions (see figure 1). The cognitive role and the ficity and establishes relationships between proper- logic of a generic schema (referring in this case to ties within a system. It asks architects to start with architectural knowledge of column types and vari- the design parameters and not preconceived or pre- ables) can also be demonstrated by examples of the determined design solutions."(Karle & Kelly, 2011)Be- Classical Greek columns (see figure 2). yond being merely a new digital technique, paramet- These two examples represent the distinc- ric design thinking is more about an understanding tion between generic typological-schema referring of parametric structures of design knowledge that to typological design of different types versus a

Generative Design - Concepts - Volume 2 - eCAADe 33 | 479 topological-schema referring to topological forma- code (or 3D re-modeling by Rhino). This presents a tion by changing the value of parametric variants of typical process of visual reasoning in which a para- the Greek Columns.Please also write your "reply to metric modification process of the script maintains the reviews" directly in the paper, using notes such the parametric relationships that have been defined as this one to point out where you have reacted to and generated. the inputs given. Tools, Scripting and Coding of Parametric Design Process Figure 1 Understanding and developing methods of pro- Classical variation graming such as parametric scripting and coding for of the generic order various process-based models of digital design are of the Greek Temple providing a foundation for the characterization and (Wikipedia) conceptual definition of parametric design thinking. In order to represent processes of parametric de- sign there is a need to explicate the flow of informa- tion and the logic that is embedded in process mod- els of design focusing on the explication of knowl- edge structures and the order of flow of informa- tion; the constructive logic should become explicit. In parametric modeling of digital models of design (for example: Grasshopper) there are two types of vi- Figure 2 sual display. An interactive display of the visual im- Schema for age is generated in parallel to interactive program- topological ing by visual scripting code. Parametric variations of formation of a Doric the image can be updated and generated simultane- Greek Column ously in a visual display in parallel to code modifica- (Credit: Michael tion. The following figure illustrates the linked dual Weizmann) provision of the visual interface for interactive code The Role of the Visual Representation in input and the resultant 3D graphical representation Parametric Schema (Oxman 2016) (see figures 3-6). Traditional representations in design are focused Understanding how a parametric schema sup- upon visual and geometrical representation of the ports the logic of a digital process model in de- design object. Visual representations are generally sign (Oxman, 2006) requires skill and knowledge that non-explicit with respect to presenting the structural includes parametric design, theories of topological logic behind form making and the development of structures and their relations, mathematics, and as- the object under design. sociative geometry. In visual parametric schema the designer inter- acts with parametric modeling using visual code Figure 3 symbols. The image of the design is generated by Schema for the 3D Rhino modeling component of the system. topological The parametric capability of a Grasshopper system formation of a enables generation and modification of the design Corinthian Greek by changing the parameters rather than rewriting the Column (Credit: Michael Weizmann)

480 | eCAADe 33 - Generative Design - Concepts - Volume 2 Figure 4 of a comprehensive theory of PDT in parametric de- Visual scripting in sign in architecture is a comprehensive and impor- performative model tant undertaking. of digital design Such a comprehensive theory would be based (Oxman 2016) upon the distinctive concepts and models of para- (Credit: I. Musizuk) metric design thinking and their impact on the for- malization of distinctive forms of information flow in parametric models of design. This would include a comprehensive formulation of the generic cogni- tive and computational reasoning models that are applied in processes of parametric design. Figure 5 It appears to have now become important to Visual 3D image in understand the role of parametric tools on design performative model thinking. We have here made a first attempt to con- of digital design tribute to the definition of PDT, its dominant con- (Oxman 2016) cepts, theories, models, and its emerging research (Credit: I. Musizuk) agenda. Given the rapid development and the broad acceptance of parametric design tools, the further ex- tension of this research agenda as well as the defini- tion of its intellectual resources appears to be a high priority agenda for and the digital design community.

ACKNOWLEDGEMENT Figure 6 The images presented in this article are based on Visual image experimental work developed by Illia Musizuk and resulting of Michael Weizmann under the supervision of Profes- algorithmic sor Rivka Oxman of the Technion, Faculty of Architec- scripting in ture and T.P. generative model of digital design REFERENCES (Credit: I. Musizuk) Celani, G and Vaz, C 2012, 'CAD Scripting And Visual Pro- gramming Languages For Implementing Computa- tional Design Concepts: A Comparison From a Peda- gogical Point of View', International Journal of Archi- tectural Computing, 10, pp. 121-138 Conclusions Hernandez, C.R.B. 2006, 'Thinking parametric design: in- We have introduced and explored a range of research troducing parametric Gaudi', , R. Ox- issues in the characterization and definition of PDT man (ed.) special issue on Digital Design, 27, pp. 309- in architectural design. Certain basic terms and con- 324 cepts have been discussed in order to provide a the- Holland, N 2011 'Inform form perform', Proceedings of oretical framework for defining PDT. The clarification ACADIA 2011 Iordanova, I 2009 'Parametric methods of exploration of the taxonomic, epistemological, and theoretical is- and creativity during architectural design: A case sues in PDT has been outlined. Further development study in the design studio', Proceedings of CAAD Fu-

Generative Design - Concepts - Volume 2 - eCAADe 33 | 481 tures 2009, Jabi, W (eds) 2013, Parametric Design for Architecture, Laurence King, London Jacoby, L 2007, 'Typological Formations: Renewable Building Types and the City', in Steele, B (eds) 2007, Serial Sensibilities, AA publications Karle, D and Kelly, B 2011 'no title given', Proceedings of ACADIA 2011 Oxman, Rivka 1997, 'Design by Re-Representation- A Model of Visual Reasoning in Design', Design Studies, 18, pp. 329-347 Oxman, Rivka 2006, 'Theory and Design in the First Dig- ital Age', Design Studies, R. Oxman (ed.) special issue on Digital Design, 27, p. 229–265 Oxman, Rivka 2014 'Parametric Design Thinking', DCC Workshop Oxman, Rivka 2016, 'The Role of the Image in Digital Design: Processing the Image versus Imaging the Process” in Inge Hinterwaldner and Sabine Ammon (eds.) Springer-Verlag', in Hinterwaldner, I and Am- mon, S (eds) 2016, Imagery in the Age of Modelling: Operative Artifacts in the Design Process in Architec- ture and Engineering, Springer-Verlag Oxman, Rivka and Oxman, Robert (eds) 2014, Theories of the Digital in Architecture, Routledge, U.K. Woodbury, R 2010, Elements of Parametric Design, Rout- ledge, N.Y Yu, R, Gu, N and G, J 2014, 'Architects' cognitive be- haviour in parametric design', International Journal of Architectural Computing, 13, pp. 83-101

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