1. A method for compressing a mesh model having geometry information and connectivity information of vertices, comprising: defining a first set of vertices all having a same valence; determining a subset of the first set of vertices that are encompassed by an area defined by the first set of vertices; encoding the mesh model by a processor without the connectivity information for the subset of the first set of vertices; and encoding the mesh model with the connectivity information for a second set of vertices, the second set comprising (1) a first group including all vertices having different valence from the first set of vertices and (2) a second group including boundary vertices having the same valence of the first set of vertices.