Research And Implementation Of Subdivision Surface Modeling Technology

Recently, the Subdivision surface behaves best in modeling complex free-form surface among existing methods, for it not only preserves several advantages of traditional NURBS, especially the properties of local controllability and affine invariance, so it has become an important research item in international Computer Graphies. Especially, in computer animation and surface modeling ,it had achieved great success. But there are still many difficulties to extend it to engineering application. This thesis mostly researches the implementation of subdivision surface modeling technology, including the following points:1. The history of subdivision surface is briefly introduced, and the base theory is also addressed. An overview of typical subdivision schemes is investigated and the properties of these schemes are summarized.2. In this paper, some typical subdivision schemes, such as Doo-Sabin subdivision, Catmull-Clark subdivision, Loop subdivision, are implemented, and a particular description of the implementation is given. The principle of selecting subdivision schemes is summarized, by comparing different characteristic of the algotithm.3. It is also well known that after subdivision,the mesh M^j+1 of next level almost needs four times memory to store new vertices,edges,faces than the mesh M^j does,so the memory needed for the storage will increase exponentially. An adaptive refinement based on the angle between two surfaces is implemented and based on the average angle between normal vector, a new adaptive refinement in Doo-Sabin subdivision scheme is presented. By adaptive subdivision, data increasing with exponential rate is avoided, and the efficiency of data transmission and process is well improved.4. Two new methods of avoiding split with Doo-Sabin subdivision scheme are presented to guarantee the quality and continuity of subdivision surface.5. A subdivision modeling system is designed with Visual C++6.0 and OpenGL to accomplish some basic operations and the algotithm in this thesisi. Through plentiful practical example, the algotithm in this thesis are proved to be right and feasible.