Abstract
The 3-D Computer-Aided Design systems have the fabulous form definition function which realized great contribution in the conceptual phase of the design process by promoting of streamlining. However, when the user tries to develop his ideas by using the 3-D Computer-Aided Design systems in the early stage of the design process, his ideas may be disturbed or limited because the 3-D Computer-Aided Design systems are built on the accurate form definition. Indeed, the designers usually convert their ideas into tangible forms by drawing rough sketches. 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.
