WIRE-FRAME MODELS 

The wire-frame model is perhaps the oldest way of representing solids. According to this model, any solid is represented by its edges and vertices. A wire-frame model consists of two tables, the vertex table and the edge table. Each entry of the vertex table records a vertex and its coordinate values, while each entry of the edge table has two components giving the two incident vertices of that edge. A wire-frame model does not have face information. For example, a cube given in Figure 6.1 is defined by eight vertices and 12 edges. One needs the following Tables(a) and (b) for complete information on the cube