Level set surface editing operators

Figure 1: Surfaces edited with level set operators. Left: A damaged Greek bust model is repaired with a new nose, chin and sharpened hair. Right: A new model is constructed from models of a griffin and dragon (small figures), producing a two-headed, winged dragon. We present a level set framework for implementing editing oper-ators for surfaces. Level set models are deformable implicit sur-faces where the deformation of the surface is controlled by a speed function in the level set partial differential equation. In this paper we define a collection of speed functions that produce a set of sur-face editing operators. The speed functions describe the velocity at each point on the evolving surface in the direction of the sur-face normal. All of the information needed to deform a surface is encapsulated in the speed function, providing a simple, unified computational framework. The user combines pre-defined building blocks to create the desired speed function. The surface editing op-erators are quickly computed and may be applied both regionally and globally. The level set framework offers several advantages. 1) By construction, self-intersection cannot occur, which guarantees the generation of physically-realizable, simple, closed surfaces. 2) Level set models easily change topological genus, and 3) are free of the edge connectivity and mesh quality problems associated with mesh models. We present five examples of surface editing opera-tors: blending, smoothing, sharpening, openings/closings and em-bossing. We demonstrate their effectiveness on several scanned ob-jects and scan-converted models