Abstract
Today's computer-aided design (CAD) systems are based on underlying technologies developed over 20 years ago. Although they have become a key part of the design process and are ubiquitous in industrial product development processes, they usually come into play after the shape of the design has been created. In essence, today's CAD systems are used to support design evaluation and analysis and downstream applications such as manufacturing. Our research challenge was to bring computers into the start of the creative design process, where they can augment design activity by supporting design synthesis - enhancing and highlighting options that might be open to the designer. Our vision was of a computer aided design synthesis system that can work with and manipulate designers' sketches at the earliest stage of the design process. Previous research in the application of shape grammars to design generation indicated that they offered a potential foundation upon which such a system could be built.