Abstract
This paper deals with an interface system which is effective in the conceptual phase of the design process. The interface system recognizes primitives: cylinders, cones, spheres, and cuboids from sketches of functional components drawn by a designer and constructs 3-D models. The algorithm of the system is so built as not to obstruct thinking design of the designer. The results show that the recognition of the primitives has been done correctly, and the implementation of the system in a 3-D Computer-Aided Design system can help the designers to shorten the time of designing.
