Supporting Creative Mechanical Design

Knowledge-based CAD systems limit designers’ creativity by constraining them to work with the prototypes provided by the systems’ knowledge bases. We investigate knowledge-based CAD systems capable of supporting creative designs in the example domain of elementary mechanisms. We present a technique based on qualitative explanations which allows a designer to extend the knowledge base by demonstrating a structure which implements a function in a creative way. Structure is defined as the geometry of the parts, and function using a general logical language based on qualitative physics. We argue that the technique can accommodate any creative design in the example domain, and we demonstrate the technique using an example of a creative design. The use of qualitative physics as a tool for extensible knowledge-based systems points out a new and promising application area for qualitative physics.