The aim of surface modeling systems is to completely represent geometric form of a free-form 3D object. In surface modeling, you use edges and surfaces to define the geometry of objects. (See Figure 1.) With this representation, you can visualize the model and retrieve the coordinates of any points on the surface.
Figure 1 Edges and surfaces
Using surface model, you can generate shaded images for visualization, geometric data for Finite Element Analysis (FEA), and tool paths for Computer Numeric Controlled (CNC) machining. Using current technology, you can precisely construct regulated complex surfaces and sculpt the surfaces flexibly. Certain computer modeling systems also enable you to convert a surface model to a solid model and vice versa