N-sided holefilling and vertex blending using subdivision surfaces

Abstract

To fill an N-sided hole on a NURBS surface and to blend a corner formed by NURBS surfaces,we propose a regular N-sided open uniform quadratic subdivision surface derived by applying the open uniform quadratic subdivision scheme to an initial regular N-sided control mesh which confines to the hole or the region of the vertex blend. The boundary conditions required for hole filling and vertex blending are ensured by certain refinement steps in the course of the subdivision. The shape of the filling or blending surface can also be controlled by fullness parameters. The resulting regular N-sided open uniform quadratic subdivision surface is finally represented or approximated by NURBS surfaces.