Opengl In 3d Modeling Applications

3D CAD model can express external characters and structure characters of a manufacture clearly. The continual development of computer technology has made 3D modeling~. rendering and animate technolodgy into reality,and has provided external condition for the development of the manufacturing. At the same time, because a large amount of engineers have strongly demand that 3D design can replace previous 2D design, it is a very important that project a series of 3D CAD system that is fit for Chinese designers. Since Microsoft Inc has encapsulated graphic libraries of OpenGL into Visual C++2.O and above editions, more PC users are able to make good use of OpenGL and rapidly design highquantity 3D graphic. On the right base, This paper is designed to study how to display realistic 3D graphic. All the work is done on the VC++5.O platform and using object-oriented method and OpenGL graphic libraries.OpenGL graphics library provides perfect graphic control funtions.But OpenGL is not good at model ,since only provide the representation funtion of drawing and rending vertex,line and polygon.Transformation and process must be made using OpenGL.The surface of 3D solid represented by similar boundary representation model is decomposed with monotone chain decomposition method, which improves the insufficiency on the arbitraty polygon .a good realistic display is obtained using the technique described above.