Catmull-Clark subdivision surface (CCSS Generalization of uniform bicubic B-spline surface C2 continuous except at extraordinary points The limit of a sequence of recursively refined control meshes initial mesh step 1 limit surface Generalization of uniform bicubic B-spline surface ◼ continuous except at extraordinary points  The limit of a sequence of recursively refined control meshes Catmull-Clark subdivision surface (CCSS) initial mesh step 1 limit surface 2 C