B-spline surfaces over an irregular topology by recursive subdivision

The technique of recursive subdivision can be visualised, loosely, as successively chopping off the corners of a polyhedron to make it less pointed. If the polyhedron is represented as a mesh of points connected by edges, repeated application of the subdivision results in progressively finer meshes tending in the limit to a surface. The subdivision is determined by the weightings given to the respective points and their neighbours