The fast rendering of virtual scene is a key technology of virtual reality. To express the virtual scene in natural, people use 3D model to construct the virtual scene. While the accuracy of these 3D models grows with the development of the modeling techniques, the volume of the data sets grows even rapidly. It brings great pressure to the rendering of the computer. Our work mainly focuses on the simplification of virtual scene and fast rendering. The work mainly consists of the following aspects: To preserve the major feature of the modeles, we developed an algorithm based on shape feature to improve progressive mesh simplification method. We give the definition about shape feature in detail, and it can describe the major feature perfectly, which overcome the drawback of quadric error metric method that is easy to lose the model feature under low-resolution circumstance. We employ Metro detection and image comparison to verify the error measurements. Experimental results demonstrate the effectiveness of the proposed method. As for automatic gerenating Lod model of the large-volume 3D model, we designed a distributed framework for the simplification of massive mesh. To reduce the time of processing, we developed a fast and simple scheme for lossless, on line compression method to reduce the time of transmit between the network. The validity of framework is demonstrated by the experiment results. From the point view of real-time graphics rendering, we proposed a view-dependent simplification algorithm based on probability occlusion culling. View-dependent rendering provides the ability to change level-of-detail smoothly in real-time. However, many occluded regions will be rendered in high level-of-detail， which reduced the frame rate.To overcome this drawback, we estimate the occlusion factor and fastly determine the degree of occlusion of region with respect to the viewpoint. The region with high degree of occlusion will be rendered in low level-of-detail. At the same time we take advantage of coherence between consecutive frames to improve the fame rate. Experiment result demonstrates the effectiveness of the proposed method. Based on the theory of fast rendering, we applied the key technology to the airport traffic controller simulation and validation system, the simulation ability of the system can be improved. The main framework for constructing airport traffic controller distributed simulation system is brought forward. Combined with the environment of project, the design of the system and developing flow are discussed in detail from several aspects, such as function module, configuration, etc. The result of the system operation shows that the frame rate of the scene has been improved greatly by the application of our key technology.
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