Constant section elements are to be found throughout today's automobile. Included in this classification are structural members, drip rails, windshield and backlight moldings, and decorative body moldings. In designing these elements, as in most engineering design problems, the task is twofold. First, we have the creative aspect of the job which establishes the general shape or character of the design. This is followed by the detailed design definition. The basic problem in establishing a man-computer “design” team, where the man provides the creativity and the computer completes the details, has been the development of an effective interface between the two. With the advent of interactive graphic consoles, the interface has been provided whereby an effective man-computer team can be established. To be more specific, constant section elements can be designed by a man-computer team which uses an interactive graphic console as the communication medium. Furthermore, a better design ensues as the man is free to pursue more different designs due to the computer's ability to provide the geometric details much faster than the designer could conventionally.