Computer Illustration of Three Dimensional Sculptured Surfaces

The information content in computer generated images is often overwhelming to visually interpret. To better communicate the overall shape information of a given model, current techniques for creation of wireframes, shaded renderings. and painted images need to be augmented and used cooperatively. A system for automatically generating computer illustrations of three-dimensional sculptured surfaces is presented, based on techniques borrowed from traditional illustration. Important aspects of the models are emphasized through an increased vocabulary for lines and surfaces. Lines are drawn in different styles (solid, dashed, etc.) and with variable widths and transparencies based on object visibility and other attributes. Surface shading is also modified to allow important aspects of the illustration to remain visible. User specified rules are used to guide the illustration process, including the choice of attributes for object emphasis.