Drawn-oriented Three-dimensional Model Is Optimized

We have built a concise and powerful geometry modeling system, which is named RadM. optimized to the scenery construction and virtual avatar shaping to meet the increasing demands of Virtual Reality, computer animation and computer games. In order to optimize 3D models before store and rendering, we create a subsystem for RadM.Triangulation is a fundamental problem in computational geometry. In real time system, polygon should be triangulated in order to make full use of rendering accelerate on function of graphic hardware. The speed of high performance rendering engines on triangular meshes is usually bounded by the rate at which triangulation data is sent into the machine. We have realized stable triangulation and striping methods in RadM modeling system. Triangulation method, which is based on Delaunay triangle algorithm, has been improved on criterion of selected vertex, and striping used local optimize greedy algorithm.Billboard clouds is a new approach for extreme simplification. 3D models are simplified onto a set of planes with transparence and texture maps. This method does not require connectivity information, but instead avoids cracks by projecting primitives onto multiple planes. Garland et al. have developed a surface simplification algorithm which can rapidly produce high quality approximations of polygonal models. This algorithm uses iterative contractions of vertex pairs, to simplify models and maintains surfaces error approximations using quadric matrices. We have applied these two methods to simplify models in our system and have done some improved work on the first one.When simplifying 3D models in the extreme, billboard clouds is better than the mesh simplified algorithm. But its biggest deficiency lies in the existence of cracks between different billboards. With the coequal critical error, we could decrease cracks almost without increasing rendering cost by using surface rectification gene to improve substituted surface's locality. Utilizing the specialty of billboard's texture is rectangle, we used a simpler packing algorithm to pack re-projecting texture to one image, which effectively decrease the cost of texture memory and of exchanging texture when rendering. Based on the specialty of billboard clouds and user's need, we could have better simpler effect in certain model by localize this simple method.