Terry Knight

Computing with emergence

The concept of emergence has its roots in 19th-century philosophy. Today it is central to many computational systems which retain the hallmarks of emergence laid out much earlier. The role of emergence in creative design and its unique embodiment in shape grammars have been emphasized by March, Stiny, and others. Shape grammars generate emergent shapes—shapes not predefined in a grammar. Emergent shapes are not only the output of a shape grammar computation; they can be the input for further computation. The history of emergence and its characterization in shape grammars are discussed here. Different sorts of shape emergence in grammars are then distinguished: anticipated, possible, and unanticipated. Unanticipated emergent shapes are shapes not premeditated by the author or user of a grammar. Generally, unanticipated shapes require on-the-spot definitions of rules to compute with them. However, for some interesting design problems, it is possible to know in advance what to do with unanticipated shapes, and to predefine rules accordingly. Special rules for computing with unanticipated shapes are proposed here. These rules allow for processes that have previously been handled extragrammatically—outside of grammars—to be handled within grammars. Examples of applications of these rules within a single grammar and across parallel grammars are given.

Shape Grammars: Six Types

The issue of decidability in relation to shape grammars is considered here. Decidability concerns, first, the identification of different types of grammars and, second, the answerability or solvability of questions about these types of grammars. In this paper, the first of these two topics is examined. Six different types of shape grammars are defined by considering different kinds of restrictions on rule format and rule ordering. The effects that these different restrictions have on the generative power, practicality, pedagogical value, and other characteristics of a shape grammar are discussed. In a subsequent paper, “Shape grammars: five questions” (Knight, 1998), the answerabilities of various questions about the types of shape grammars outlined here are explored. The decidability issues addressed in this paper and the subsequent one are key to the practical use of shape grammars in design projects where specific goals and constraints need to be satisfied.

Classical and non-classical computation

Computers have come to play an important role in architectural practice. Nonetheless, the promise of computation as a creative partner in practice, and a means to better understand and support the design process has yet to be realized. This article considers aspects of computation, and alternative ways that these have been approached in order to make computation useful in architecture and other areas of spatial design.

Computing with Ambiguity

In a previous paper, emergence and ways of computing with emergence were discussed. Emergence goes hand in hand with ambiguity. Ambiguity, of a particular kind, is foundational in shape grammars. Shape grammars compute with shapes that have ambiguous or indefinite parts. This part ambiguity is exploited easily and well in shape grammar computations. Another kind of ambiguity is considered here. This is representational ambiguity—an ambiguity of the nature of the elements that make up shapes. Shapes are represented with elements—points, lines, planes, and solids—that can have ambiguous and fluid interpretations as material, conceptual, symbolic, or other entities. Like part ambiguity, representational ambiguity is integral to the beginning, exploratory stages of a design process. Among the best and most explicit treatments of representational ambiguity were those given by two prominent design theorists of the 20th century, Wassily Kandinsky and Paul Klee. Informal examples of representational ambiguity from the writings of Kandinsky and Klee are reviewed here. These are used to motivate ways of handling representational ambiguity computationally. New kinds of algebras for shape grammar computations that support some of the ambiguities suggested by Kandinsky and Klee, as well as other kinds, are proposed.

Color Grammars: The Representation of Form and Color in Designs

Recent developments in the use of formal grammars in design are summarized here. A particular kind of formal grammar, called a shape grammar, has been used widely over the past decade to understand the spatial composition of designs in architectural and other languages. Recently, an extension to the shape-grammar formalism has been developed that allows qualities such as color, texture, material, function, and so on, to be incorporated into the rules of a shape grammar. This new kind of grammar, called a color grammar, can be used to represent simultaneously the composition of spatial and qualitative aspects of designs. Simple, pedagogical examples of color grammars are presented. Issues that arise with the representation of color or other qualities in grammars but do not arise with the representation of spatial form are discussed.

Designing a Shape Grammar

Shape grammars are classified into different types according to restrictions on rules. The predictabilities of the outcomes and behaviors of these different types of shape grammars are examined. Understanding the predictabilities of grammars is central to the successful design of shape grammars in creative design applications.

Looks count: Computing and constructing visually expressive mass customized housing

Abstract This paper introduces new research that seeks to develop low-cost, high quality, mass customizable building assembly systems that provide visually rich design variations for housing or other small structures. The building systems are intended to be tailored for particular cultures and communities by incorporating vernacular decorative design into the assembly design. Two complementary research areas are brought together in this work: shape grammars and digital fabrication. The visual, aesthetic aspects of the research are explored through shape grammars. The physical design and manufacturing aspects are explored through advanced digital design and fabrication technologies, and in particular, build on recent work on monomaterial assemblies with interlocking components that can be fabricated with computer numerical control machines and assembled easily by hand. The long-term objective of this research is the development of formal, visual–physical grammars with rules that generate complete computer-assisted design/computer-assisted manufacturing data for fabrication of full-scale components for assembly design variations. This paper reports on the first phase of this research: pilot studies for prototype assembly systems that incorporate vernacular languages from different parts of the world. The results of these studies are very promising, and demonstrate a spectrum of strategies for embedding visual properties in structural systems. Important next steps in this research are outlined. If successful, this work will lead to new solutions for low-cost, easily manufactured housing, which is especially critical in developing countries and for postdisaster environments. These new housing solutions will not only provide shelter but also support important cultural values through the integration of familiar visual design features. Beyond the specific context of housing and building assemblies, the research has the potential to impact the design and manufacture of designed artifacts on many scales and in many domains, especially in domains where visual aesthetics need to be considered jointly with physical, structural, or material requirements, and where design customization and variation is important.

Shape Grammars: Five Questions

In the paper “Shape grammars: six types”, the issue of decidability in relation to shape grammars was introduced. Decidability concerns, first, the identification of different types of grammars, and, second, the answerability or solvability of questions about these types of grammars. The first of these two topics was explored in “Six types”. Six different types of shape grammars were defined in terms of different restrictions on rule format and rule ordering. The generative power, practicality, pedagogical value, and other characteristics of each type of shape grammars were discussed. In this paper, the second of the two topics in decidability is addressed. Five questions about the different types of shape grammars defined in “Six types” are posed. These questions are formulated for their practical value in design applications of shape grammars, as well as their theoretical interest. The answerability of each question is examined in detail for each type of shape grammar.

Infinite Patterns and their Symmetries

Some ambiguities and curiosities that arise in the representation, construction, and symmetry classification of infinite patterns are examined. The discussion focuses on frieze patterns, a simple kind of infinite pattern. The examination of these patterns from a generative perspective—that is, in terms of rules that apply to construct them—reveals unusual characteristics of friezes.

Either/or → and

The writings of Wassily Kandinsky and Paul Klee, Bauhaus theorists and pioneers of nonrepresentational art, are the framework for a discussion of contemporary issues in computational design. Kandinsky and Klee wrote of the many misguided dualisms in the art theory and pedagogy of their time. They sought to reconcile the seemingly mutually exclusive issues associated with abstraction in art. Some of these dualisms, and new ones, arise today in discussions of computational design. How and whether these dualisms can be reconciled in computational design are considered here.