Intersection of straight line segments 103 Non-linearity and the intersection of curves 109 Subdivision and box-testing techniques 114 Closed curves 120 A data structure for closed curves 123 The merging of closed curves 125 Chapter 5: Representation of surfaces 133 Introduction 133 Ruled surfaces 134 Coons' patches 136 Surfaces through given points 141 Bezier surface patches 143 B-spline surfaces 148 The DUCT system 149 Problems involved in putting patches together 153 Chapter 6: MODCON: an example system 159 Background to the system 159 The use of primitive shapes 160 Putting primitives...