Exploring the Integration of Spatial Grammars and Open-Source CAD Systems
While Computer Aided Design (CAD) has made significant progress since its inception, CAD tools are still used primarily for design documentation rather than as active partners in the design process. Shape and spatial grammars provide methods for interactive, generative shape design but have yet to find general application within CAD systems. This paper investigates the potential for integrating spatial grammars and an open-source 3D modeling kernel and CAD system. The definition of a vocabulary of shapes based on a library of solid primitives and use of standard functions like geometric transformations and Boolean operations in rule applications are explored. Two examples illustrate the approach: the Kindergarten grammar and vehicle wheel rim designs. Advantages include (1) from an implementation viewpoint of spatial grammars, the coding effort decreases by making use of standard 3D modeling functionality, (2) from a usability viewpoint of spatial grammars, the combination improves the potential practical use of spatial grammars in CAD processes and (3) from a CAD viewpoint, spatial grammars provide an integrated means for automated, flexible generation of design alternatives.