Research Subdivision Surface Technology Base On Quadrilateral Meshes

Subdivision scheme has been an important tool of computer graphics for recent years, and it is one of the hotspot of computer aided geometry design. The basic idea of subdivision scheme is to get smooth surface modeling from coarse and simple surface modeling through adding new vertices. Subdivision scheme can control arbitrary topology meshes. It not only can keep whole smoothness of surface, but also can reserve some local characters. The thesis researched Quadrilateral mesh subdivision surfaces modeling techniques from different points of view in order to further improve modeling abilities of subdivision surfaces.After introducing the subdivision surfaces on the basis of the research present status and related knowledge, this paper proposed a parameters subdivision, the winged edge ways to establish data structure. A new algorithm to design adjustable subdivision surfaces using two control parameters was presented in this paper. A kind of subdivision surfaces can be constructed by changing one of the parameters. Meanwhile, the shape of the subdivision surface can be adjusted by using another control parameter. From some examples, the subdivision design algorithm was given to demonstrate the freedom and efficiency of the algorithm. This method can be arbitrary edges to topology, and on the shape of the initial mesh no strict restrictions, an increase of subdivision surface modeling flexibility.Regarding some not smooth special effect situation in geometric modeling the surface, this paper proposed certain processing rule and has carried on corresponding processing. At last this paper proposed one new quadrangle mesh subdivision method, this method has made the improvement to the topological rule and the geometric rule. In contrast to the usual binary splitting operation, the number of quadrilaterals increases in every step by a factor of 2. Applying the subdivision twice is the same as a binary subdivision. The resulting surface is C2 continuous for regular vertices and C1 continuous for extraordinary vertices and the simplicity in geometric operation. The slow topological refinement made the subdivision scheme described in this part more suitable for many applications.