14. Implementing Shape Grammars for Designers

For the computational understanding of visual artifacts, shape grammar provides an important theoretical framework. In addition to the theory, there have been numerous computer implementations; these have tended to be proofs of concept. As such, they are essential steps in development, but do not directly help researchers do the kind of analyses seen in the literature, which were done by hand. That is to say, we have a theory but not yet a sturdy tool. We present a prototype implementation to help designers and design researchers work with shape grammars. This implementation allows users to focus on domain tasks—editing and testing grammars—by shielding them from sub-domain tasks—mechanical tasks like matching shapes and applying rules. A grammar is displayed as a collection of shapes in 3D space that users can manipulate directly; a commercial 3D modeling application is used for this purpose. The components of the implementation are designed to make it easy for users to switch between editing and testing their grammars. The implementation handles emergence and is general. We report on users’ experiences with the implementation in workshops on grammatical design and analysis.