AUTOMATIC SURFACE GENERATION WITH A VOXEL-BASED SKELETON DEFINING TOPOLOGICAL CONSTRAINTS

Abstract

Shape design is often performed by starting from a basic surface and by refining it afterward by adding details. In order to construct this first approximation surface, we present in this article a method to generate a basic polyhedron from a volumic voxel-based skeleton. This approach preserves the topology described by the discrete skeleton in a 3D grid considering the 26-adjacency: if a cycle is sketched, then there is a hole in the resulting surface, and if a closed hull is designed, then the output has a cavity. We verify the same properties for connected components. This surrounding basic polyhedron is computed with simple geometrical rules, and it is a good starting point for 3D shape design from a discrete voxel skeleton. In order to add multiresolution features to our approach, we use this rough mesh as the control polyhedron of a subdivision surface, according to the Loop scheme dedicated to triangulated surfaces. We show that the resulting set of smooth refined meshes is well suited for further modifications in the frame of a 3D modeling software.