Manipulating Shape and Its Function

Abstract

Shape and other geometric information about design objects play a pivotal role in design. Shape grammars provide a technique to manipulate and reason with shape. A shape grammar consists of a set of productions on rules for composing shapes out of primitive entities called terminal symbols. This paper presents shape grammars and describes two applications in which shape grammars are combined with functional reasoning for design. The first application illustrates the design of a modular retaining wall. The shape grammar controls the placement of the wall components, and a functional rule selects the strength of each component. The shape grammar is used to generate wall layouts as well as to critique existing layouts. The second application illustrates the integration of structural and architectural design of buildings through the manipulation of common spatial objects. The design system uses knowledge‐based techniques to determine high‐level structural and architectural functional information, and the shape grammar places the structural objects (columns) satisfying the functional requirements. The advantages and disadvantages of shape grammar techniques are discussed.