Hidden Curve Elimination of Trimmed Surfaces Using B ezier Clipping

Shaded display is popular for displaying curved surfaces because of the realistic appearance of the images produced. In the eld of computer aided geometric design, however, line drawings are more commonly used. For accurate evaluation of the curved surfaces in these designs, the conventional method of approximating curved surfaces with polygons is insu cient. In this paper we will present a method of hidden line elimination without resorting to polygonal approximation. The method provides the designer smoother, more precise isoparametric curves than traditional polygonal approximation methods. In addition, the method can draw precise silhouette curves, trimming curves, drawings of patterns represented by curves on the surface, and contour lines. Furthermore, the method is valid even for surfaces which penetrate each other.