Research On Blending Methods For Subdivision Surfaces And NURBS

Subdivision method is now becoming a powerful implement of surfacerendering. The purpose of this paper is to study the relationship betweenDoo-Sabin subdivision surface,Catmull-Clark subdivision surface and NURBS.So as to integrate subdivision method with NURBS method. Based on Doo-Sabin subdivision surface and quadratic C-B splines, We putforward an algorithm that builds a kind of quasi-Doo-Sabin subdivision surface.With the indraught of the basic function in C-B splines which contain sinefunction, cosine function and controls parameter, the new algorithm can generategeneral engineering surfaces such as cylinder surface. At the same time, owe to thecontrol action of the controls parameter, the reconstructive subdivision surfacekeep consistence with Doo-Sabin subdivision surface. Another work in this paper is about surface blending and N-sided hole filling.Based on the N-sided surface which is constructed by non-uniform Catmull-Clarksubdivision method and figure deleting method, We present the material algorithmto blend some non-uniform bi-cubic B-spline surfaces and to fill an N-sided holewhich is surrounded by non-uniform bi-cubic B spline surfaces. What's more, bychanging the parameter of the sides near the boundary, we put forward anothermethod to construct N-sided surface which build the surface interpolating cornervertices and boundary curves. This N-sided surface is also fallen under thenon-uniform Catmull-Clark subdivision surface with figure deleting method. Analysis and demonstration show the feasibility and efficiency of thealgorithms.