Sharp Feature Modeling of Doo-Sabin Subdivision Scheme

By generalizing knot-inserting algorithm of quasi-uniform quadratic B-splines,subdivision rules for Doo-Sabin scheme in feature faces,such as boundary faces,crease faces and corner faces etc,are presented and sharp features,such as boundaries,creases,darts and corners can be generated without any topology constrains.Continuity analysis near these features shows that the resulting limit surfaces are of piecewise G¹ smoothness.Complicated surfaces of arbitrary topology with sharp features and quadratic surfaces frequently used in engineering,such as spheres,cylinders and cones,can also be accurately represented,which indicates the broad applicability of our method in CAD/CAM fields.