A regular 3ds Max mesh and consists of faces and vertices; it has no edge data members. Edge characteristics such as visibility and selection are referenced by face. For example, the Mesh::edgeSel data member has 3 * Mesh::numFaces members. Each set of three values edgeSel[i*3], edgeSel[i*3+1], and edgeSel[i*3+2] represent the selection of the three edges (going from vertex 0 to vertex 1, vertex 1 to vertex 2, and vertex 2 to vertex 0, respectively) of face i.