Determine the Edge Table
Each entry in the edge table contains those information mentioned earlier, edge name, start vertex and end vertex, left face and right face, the predecessor and successor edges when traversing its left face, and the predecessor and successor edges when traversing its right face. Note that clockwise ordering (viewing from outside of the polyhedron) is used for traverse. Note also that the direction of edge a is from X to Y. If the direction is changed to from Y to X, all entries but the first one in the following table must be changed accordingly.