Multiresolution Representation Of Subdivision Surface For Preserving Sharp Feature

With the rapid development of computer technology, Internet system and3D scanning devices, the3D surface modeling technique plays an increasingly important role in many application fields. Because of the excellence of fast generation of smooth model simply and intuitively on arbitrary meshes, subdivision method has become one of the most important tools for3D surface modeling and has broad application prospects. As the technology which combines subdivision method with wavelet transform and the theory of multi-resolution analysis, subdivision method presents increasingly booming vitality. It has become one of the most important free-form surface design techniques following NURBS method.Under normal circumstances, with the given subdivision schemes, the limited surface of the mesh is fixed and smooth. But in actual applications, all sorts of geometric sharp features such as cone, crease and groove are needed to simulate the real object. Actually, these unsmooth geometric sharp features are usually the important bases for object recognition.Considering the widely used of triangle meshes, this article focuses on the implementing of multiresolution representation of Loop subdivision based on triangular mesh, and aims to develop some new methods for solving the existing problems of the current feature modeling methods and subdivision methods in practice. This paper is composed of several aspects as follows: Firstly, an efficient algorithm of adaptive Loop subdivision surfaces for preserving sharp feature is proposed, and this algorithm requires less memory but keeps sharp features better in subdivision processing with a new flatness defined by the paper.Secondly, the traditional Loop subdivision method is modified to a new adjustable and adaptable subdivision method by incorporating a controllable factor. By this adjusting control factor, different semi-sharp feature modeling result can be generated. Finally, a subdivision wavelet transform algorithm based on preserving sharp feature is brought out and it can reserve main features in diverse resolution of subdivision surface. In addition, a subdivision surface modeling system, which has realized several classical subdivision methods and all the above algorithms, is explored with Visual C++6.0and OpenGL. Various types of file formats such as obj,3ds, tm and smf can be imported and be processed to the subdivision surface modeling system. The subdivision surface modeling system provides very rich interface functions, which allows the user to create an interactive process, generating a series of3D modeling, and their control. The result of experiment has indicated that the system realized all the above algorithms proposed by this paper with excellent effect.