Self-intersection of an offset surface

Abstract A method is described for obtaining the self-intersection curves of a collapsed offset surface. The method comprises two essential processes. The first is to detect the self-intersection points of a collapsed offset surface by successive unidimensional searches. The second is to calculate self-intersection curves by numerical integration by using some of the points obtained in the first process as initial points. All offset surface data needed is directly generated from the original surface without offset approximation. This method is applied to some collapsed offset surfaces whose original surfaces are defined by a B-spline.