Representation and reasoning about shapes: Cognitive and computational studies in visual reasoning in design

This paper describes some recent cognitively-based and computationally-based research on representing and reasoning about shapes. The cognitive studies are based on protocol analyses of designers and indicate that visual reasoning in design involves drawings of shapes and their relations in the generation of unexpected results. The computational studies are concerned with the development of qualitative representations of shapes that can be used to reason about shapes. Two representations are described: half-planes and landmark-based qualitative codes. Reasoning using these representations is presented.