T-spline Simplication and Local Renement

A typical NURBS surface model has a large percentage of superuous control points that signicantly interfere with the design process. This paper presents an algorithm for eliminating such superuous control points, producing a T-spline. The algorithm can remove substantially more control points than competing methods such as B-spline wavelet decomposition. The paper also presents a new T-spline local renement algorithm and answers two fundamental open questions on T-spline theory. CR Categories: I.3.5 [Computer Graphics]: Computational Geometry and Object Modelingocurve, surface, solid and object representations;