CGA shape, a novel shape grammar for the procedural modeling of CG architecture, produces building shells with high visual quality and geometric detail. It produces extensive architectural models for computer games and movies, at low cost. Context sensitive shape rules allow the user to specify interactions between the entities of the hierarchical shape descriptions. Selected examples demonstrate solutions to previously unsolved modeling problems, especially to consistent mass modeling with volumetric shapes of arbitrary orientation. CGA shape is shown to efficiently generate massive urban models with unprecedented level of detail, with the virtual rebuilding of the archaeological site of Pompeii as a case in point.

is provided in screen-viewable form for personal use only by members

Abstract not found

This paper presents a new method for the automatic modeling of architecture. Building designs are derived using split grammars, a new type of parametric set grammar based on the concept of shape. The paper also introduces an attribute matching system and a separate control grammar, which offer the ßexibility required to model buildings using a large variety of different styles and design ideas. Through the adaptive nature of the design grammar used, the created building designs can either be generic or adhere closely to a speciÞed goal, depending on the amount of data available.

In exploring the question of whether a computer program is behaving creatively, it is important to be explicit, and if possible formal, about the criteria that are being applied in making judgements of creativity. We propose a formal (and rather simplified) outline of the relevant attributes of a potentially creative program. Based on this, we posit a number of formal criteria that could be applied to rate the extent to which the program has behaved creatively. A guiding principle is that the question of what computational mechanisms might lead to creative behaviour is open and empirical, and hence we should clearly distinguish between judgements about creative achievements and theoretical proposals about potentially creative mechanisms. The intention is to focus, clarify and make more concrete the debate about creative programs. 1

Physically-based modeling has been used in the past to support a variety of interactive modeling tasks including free-form surface design, mechanism design, constrained drawing, and interactive camera control. In these systems, the user interacts with the model by exerting virtual forces, to which the system responds subject to the active constraints. In the past, this kind of interaction has been applicable only to models that are governed by continuous parameters. In this paper we present an extension to mixed continuous /discrete models, emphasizing constrained layout problems that arise in architecture and other domains. When the object being dragged is blocked from further motion by geometric constraints, a local discrete search is triggered, during which transformations such as swapping of adjacent objects may be performed. The result of the search is a "nearby" state in which the target object has been moved in the indicated direction and in which all constraints are satisfied. ...

This paper describes an approach to interactive design tasks based on Relational Grammars. Relational Grammars extend traditional one-dimensional string languages to higher dimensions through user-supplied domain relations. Design support takes the form of graphic inferences on partial input during design interaction with the user. Because of the nature of the rule definitions, design elements can be roughly "sketched " without concern for their specific details. During the interaction process, the system installs constraints, adds default attributes, and/or builds higher-level composite structures out of the original input. An example scenario of the use of this formalism is presented supporting the task of document design. A general algorithm for the integration of grammarbased parsing in an interactive design environment is presented.

This paper describes a design method based on constructing a genetic/evolutionarydesign model whose idea is borrowed from natural genetics. Two major issues from the modelling involve how to represent design knowledge for the evolutionary design model and the usefulness of the model for design problems. For the representation of design knowledge in the model, a schema concept is introduced. The utility of the model is based on its computational efficiency and its capability of producing satisfactory solutions for the given set of problem requirements. The design problem used to demonstrate the approach is a large office layout planning problem with its associated topological and geometrical arrangements of space elements. An example drawn from the literature is used.

Just as there are symbolic thinkers, people who think mainly in terms of letters and numbers and other symbols, and visual thinkers, people who think primarily in terms of shapes and colors and spatial relationships, there can be symbolic computations and visual computations. Clearly, symbolic computations are much more extensively developed; digital computers are based on symbols. Shape grammars are intended to form a basis for purely visual computation. The primitives in shape grammars are shapes, rather than symbols. The relationships and operations are all spatial (e.g. similarity, rotation) rather than symbolic. One can show the formal equivalence of traditional symbolic computations and shape grammars. The proof is in two steps: show how shape grammars can be implemented on a computer and show how a universal symbolic computing mechanism, traditionally a Turing machine, can be implemented as a shape grammar. Shape grammars have been used in visual areas: in painting and sculpture, in

Creative products are generally recognised as satisfying two requirements: firstly they are useful, and secondly they are novel. Much effort in AI and design computing has been put into developing systems that can recognise the usefulness of the products that they generate. In contrast, the work presented in this thesis has concentrated on developing computational systems that are able to recognise the novelty of their work. The research has shown that when computational systems are given the ability to recognise both the novelty and the usefulness of their products they gain a level of autonomy that opens up new possibilities for the study of creative behaviour in single agents and the emergence of social creativity in multi-agent systems. The work