RATIONAL BLENDING SURFACES BETWEEN QUADRICS

Using tools from classical line geometry and the theory of kinematic m appings, it is possible to define an intrinsic control structure for N URBS curves and surfaces on the sphere, the cylinder and on any projec tively equivalent quadratic surface. These methods are further used to construct exact C-1 blends between these surfaces, such that interact ive design of trim lines and surface tension is possible. The lowest p ossible degree of a blend that can be achieved with this method is (4, 3). (C) 1997 Elsevier Science B.V.