A Methodology for Creating Shape Rules During Product Design

Shape grammars provide the means to represent the physical embodiment of a class of products in a set of generative rules. Once developed, the shape grammar can be used to generate new forms through automated synthesis or interaction by one or more designers. Creating the shape rules has been most often performed after the design process by examining existing designs. Furthermore, the approach to create a set of rules from an existing set of products was usually an ad hoc process of generalizing form, identifying feature options, and classifying logical subdivisions of the complete product geometry. This paper proposes a more explicit method of shape grammar creation, that is, aligned with well-known design methodologies in order to enable the creation of a shape grammar during the new product development process. The established methodology for function first design and design exploration provides many of the requisite steps for creating a shape grammar, connecting customer requirements and constraints to product form and provides a skeleton onto which a rule creation approach is mapped. An example is included in which the proposed methodology is used to create a shape grammar that represents the internal components of a bladeless slurry pump in order to support design exploration driven by simulation and experimentation.