Parametric design method of aesthetic shapes with smooth curvature variation

Among industrial products like automobiles, aesthetic elements have become important as well as conventional factors such as performance, quality and price. Their design process consists of several stages. In the initial stage, designers usually develop conceptual images based on 2D sketches. Though recent CAD systems have various functions, they interfere with designers' creative activity because of their incompleteness and complicatedness. Hence a new modeling method is required for designers to support their intuitive task that is usually done in the initial design stage. This paper presents a parametric design method so that designers can deal with many types of curves and surfaces with a few parameters for creating conceptual images of the product's shape. First, conditions for generating guide curves to create aesthetic surfaces by moving a curve-ruler along the curves are presented. Second, an algorithm for surface generation is proposed so that any type of plane curves can be used as a curve-ruler. Application results are shown to indicate that the presented system is effective for designers' activity.