Shape Grammars Research Articles

Speaking the Buick language: capturing, understanding, and exploring brand identity with shape grammars

Developing and maintaining a consistent brand statement is an important aspect of developing a successful product. However, maintaining that statement is difficult due in part to the inconsistent and often insufficient understanding of brand by marketing, engineering, and industrial design. This paper presents shape grammars as a method for encoding the key elements of a brand into a repeatable language, which can be used to generate products consistent with the brand. A detailed investigation into the history of Buick styling reveals the brand characteristics of the front view of Buick vehicles, which are then captured in a shape grammar.

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.

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.

Supporting Designers' Hierarchies through Parametric Shape Recognition

The need to implement shape grammars efficiently, rather than hardcode them, in a way that supports creativity through shape emergence is an ongoing research challenge. This paper introduces a shape grammar interpreter that supports parametric subshape recognition, and thereby shape emergence. The approach divides shapes into hierarchies of subshapes based on specified geometric relationships within the shape. A default hierarchy based on geometric relations often found in engineering and architectural designs is presented as an efficient example of one appropriate hierarchy. The interpreter's shape recognition and generation abilities are demonstrated with two examples: a new engineering shape grammar for the design of vehicle inner panels and a modified version of the classical ice-ray shape grammar.

Designing inner hood panels through a shape grammar based framework

A framework for a design tool based on shape grammars is presented as an effective means for supporting the early stages of design. The framework uses a shape grammar interpreter to implement parametric shape grammars, allowing the grammar to be used interactively by a designer or optimization routine. A shape grammar to design inner hood panels of vehicles is introduced as an example of a parametric engineering shape grammar, and it is used with the framework to create standard and novel designs made possible by rules that take advantage of shape emergence.

Capturing a rebel: modeling the Harley-Davidson brand through a motorcycle shape grammar

The potential for capturing brand identity within a shape grammar is discussed. A two-dimensional motorcycle shape grammar is presented, along with constraints that associate the resulting designs with the Harley-Davidson brand. Confirmation of the grammar's brand representation is shown through a customer-based survey.

… part of which deserves a closer look

It is refreshing to see yet another take on shape grammars and their representations from Knight and Stiny (arq 5/4, pp 355–372), in particular, the distinction made between process and representation, thus facilitating further categorization of a variety of generative design paradigms. The term ‘shape grammar’ as used here refers to very specific representations of shape and computational processes and is often misused. A brief web search turns up many references to shape grammars. Some are unrelated to the work described here; others reference the shape grammarians but describe paradigms which are either not grammars or utilize different representations of shape.

Automatic generation and fabrication of designs

A framework for the generation and fabrication of architectural massing designs is presented. The framework consists of a computer program, which generates designs based on shape grammars, and rapid prototyping technologies that produce physical models of generated designs. The goal is to illustrate how geometrically complex designs, difficult to produce by hand, can be generated based on a few basic shapes and rules. The software developed uses Java, Open Inventor and cutting-edge 3D graphics technology. The extension of the proposed framework to one using the World Wide Web is briefly discussed.

Algebras and Grammars for Shapes and their Boundaries

A special kind of shape algebra is defined for concurrent computations with shapes and their boundaries, together with related shape grammars. Some new types of shape grammar are defined and classified.

On the use of shape grammars as expert systems for geometry-based engineering design

Production systems have traditionally been used in engineering to aid the designer in generating designs in domains not significantly influenced by geometry. However, in geometric-based domains such as mechanical engineering, their popularity has been limited. This work proposes the use of shape grammars as the framework for engineering expert systems. Shape grammars are shown to have all the generation and analysis capabilities of traditional production systems, while being able to represent knowledge about both the functionality and the form of a product. Additionally, the parametric nature of shape grammars, their ability to deal with physical form rather than abstract elements, and their ability to recognize emergent shapes give them significant advantages over traditional production systems for geometry-based engineering design.

Supporting design through the strategic use of shape grammars

This paper is concerned with the early processes of design, particularly in the context of spatial arrangements. We are interested in the strategies that a designer uses in order to achieve success and with the opportunities that might exist for computer support. The technical device that provides the focus for the work is the concept of a shape grammar. The investigation that has taken place has looked at certain opportunities that might exist for building support systems employing shape grammars and the implications that they might have for the strategic level of design. From the exploration we conclude that the use of shape grammars to expand the strategies available to a designer and to provide computational support for exploring the implications of employing given sets of design rules is promising. Moreover, we have already identified a number of directions in which the research should be taken further.

A Micro Language: Generating MEMS Resonators by Using a Coupled Form — Function Shape Grammar

Shape grammars are shown to be capable of generating coupled form — function devices by first satisfying the minimum required functionality and then modifying the device to obtain the desired specifications. Advantages of a weighted U22 algebra in conjunction with a U12 grammar are also discussed. The approach is demonstrated by describing a shape grammar for the design of MEMS resonators.

Designing for automated construction

The majority of automated construction research and development has been bottom-up, from the construction/engineering side rather than top-down from the design end. Section 2of this paper looks at precedents in automated construction research and identifies an apparent gap in design related themes. Section 3is devoted to the introduction of a research programme which addressed topics related to the conceptual design of robotic systems for construction, and developing overall design principles for top-down architect/designer applications. The research included the derivation of simple shape grammars and a simulation research programme for understanding component connections and robotic manipulation, using a model robotic construction system remote controlled over the Internet. Section 4presents a report of the research carried out according to the programme, and introduces an example concept automated construction system designed according to the principles derived from the investigation outlined in Section 3.

Influencing generative design through continuous evaluation: Associating costs with the coffeemaker shape grammar

A grammatical approach to product design is demonstrated. In particular, shape grammars are shown to be especially useful for products that are differentiated primarily on the basis of form yet driven by function; they allow products to be designed as a sequence of well-defined steps. However, it is not always clear how to choose the sequence of rules that should be applied to generate the final shape. In this paper we demonstrate that at each stage during the process, partial designs of the final product can be used to provide feedback to the designer based on specific design objectives and thus suggest possible rule choices. We take advantage of the shape grammar for the generation of coffeemakers introduced by Agarwal and Cagan, and associate with the grammar rules expressions that model manufacturing costs. With each application of a shape grammar rule, an understanding of the overall cost of manufacturing the product is incrementally improved. Thus, at each stage of the design process the designer has an indication of what the overall cost of the product will be and how the selection of one grammar rule over another influences the final cost. Once the complete product is generated, an appraisal of its manufacturing cost is given to the designer. This evaluation methodology helps the designer understand the implications of decisions made early on in the design process. We have also verified the accuracy of this approach through the costs of some commercially available coffeemakers, generated by this method, which are comparable to the costs for those designs listed in the literature.

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.

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.

A visual implementation of a shape grammar system

Shape grammars specify a mechanism for performing recursive shape computations. A general paradigm is established for a computer implementation supporting this computation in the algebras of points and lines in two dimensions (U02 and U12). The guiding principles and the actual implementation are described.

Rule-based representation of design in architectural practice

It is suggested that expert systems storing the design knowledge of particular offices in terms of stylistic and construction practice provide a means to take considerably more advantage of information technology than currently. The form of the knowledge stored by such expert systems is a building representation in the form of rules stating how components are placed in three-dimensional space relative to each other. By describing how Frank Lloyd Wright designed his Usonian houses it is demonstrated that the proposed approach is very much in the spirit of distinguished architectural practice. To illustrate this idea, a system for assembling three-dimensional architectural details is presented with particular emphasis on the nature of the rules and the form of the building components created by the rules to assemble typical details. The nature of the rules, which are a three-dimensional adaptation of Stiny's shape grammars, is described. In particular, it is shown how the rules themselves are structured into different classes, what the nature of these classes is and how specific rules can be obtained from more general rules. The rules embody a firm's collective design experience in detailing. As a conclusion, an overview is given of architectural practice using rule-based representations.

A Blend of Different Tastes: The Language of Coffeemakers

Shape grammars, utilizing function labels, are shown to be applicable to product design. A grammar that describes a language of coffeemakers is presented and shown to generate a large class of coffeemakers currently on the market, as well as new designs that could be introduced to consumers.

Topological optimization of a bumper beam via the messy genetic algorithm

This paper introduces a technique for certain types of topological shape optimization problems, called variable primary and full grammars, which are derived from shape grammars. An industrial application is used as an example based on the optimization of an automotive structural bumper beam. The optimizer, the messy genetic algorithm, a technique more powerful than traditional genetic algorithms, does not use any derivative information on the evolution of the shape, but only simple evaluations. This technique produces interesting new designs for bumper beams, although they are not globally optimal. These new designs have moved from crenellations to more complex topologies.