A Study On Real Time Rendering And Interaction Of Big VRML Scene

The research of real time display and interaction of bigger VRML scene, is one of the research area in Computer Graphics and Virtual Reality .The result of the research could be used in Virtual City Programming, View of Virtual sight, Layout and decoration of Virtual House. The paper begins from the three key points: modeling simplification, data transform from sever to client, real time display in the process from modeling to display of VRML scene, research in modeling simplification and visibility clipping in real time rendering. Also, this paper discusses the interaction in virtual scene.This paper applies the BSP Tree arithmetic used in 3D game to partition of VRML scene ,gives the theory of BSP Tree ,discusses the excellence in combining BSP Tree and VRML to realize fast visibility clipping. Under the BSP Tree partition ,the object in the scene can be departed into two kinds: the object far from the viewpoint and the object near the viewpoint. And this paper use LOD to settle this question. The application of BSP Tree and LOD together can get fine result than only use one of them. In addition, VRML use the data structure scene graph. Fully use of the virtue of scene graph : layer structure, state inherit, reuse of object ,can simply the scene.After the research of the simplification technic, this paper gives a example: the design and realization of the virtual new school. The use with Canamo and Cosmo Worlds can cut information of no use in the model. Then use BSP Tree and LOD to optimize the scene.How the user interactive with the scene is one of the research area of this paper. The base of interaction in virtual scene is discussed, Then the realization of the interaction in virtual room. The method to view with the named path is also given.At the end of this paper, both summary and prospect of the work in this paper are given.