Table of contents : Introduction....Pages 1-4 Projective geometry in general....Pages 5-52 Practical use of four dimensional geometry....Pages 53-83 Modelling clip....Pages 85-99 Projective algorithms....Pages 101-128 Conclusions....Pages 129-130 Directions for further research....Pages 131-133 An unsolved problem: Shaded B-spline surfaces....Pages 135-139