Intersurface continuity of B-spline based solid models

One of the issues of concern in any boundary representation model is the smoothness at the abutment edges of the model surface patches. This thesis looks at the maintenance of this smoothness (continuity) between connected B-spline surfaces in a multi-surface model. This process also necessitates adopting a solid object representation which provides explicit connected surface topology information. The thesis develops the conditions necessary to realize inter- and intra- surface continuities between multiply connected B-spline surfaces which have been subjected to deformations. It also develops algorithms which impose and maintain these general continuity conditions. An example implementation is realized within the context of the Alpha-1 solid modeling system. Operators are developed for the creation of B-spline based solids and to modify their shape while maintaining the specified inter- and intra- surface continuities.