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.