Research Of Virtual Scene Generation In Virtual Reality

ABSTRACT:Virtual Reality Technology has been one of the most hot research and application directions in the field of information realm since 90's in the twentieth century. It has been widely used in the fields such as flying simulation, interactive GIS, digital earth, information visualization, architecture walkthrough, etc. These applications need not only realism complex virtual environment, but require the user can interact with the virtual scene at interaction frame rate. Virtual reality communities and other visualizations have always faced the problem that their "desirable" visualization dataset sizes. However, virtual environment's realistic and real-time display is a contradiction, how to bridge the gap between the desired and the actual hardware performance through algorithmic and software techniques is a problem. Virtual environment's real-time generation is a most critical problem in VR.Picked up Beijing Jiaotong University as a reference model, this paper contains research and experiment on how to realize realistic virtual scene based on vision sense, and also completed an interactive virtual campus which can be real-time rendering realistically. Concrete contents of this paper are as follows:1. Studied and summarized rendering technologies of virtual scene, such as texture mapping, real-time rendering, LOD, DOF etc. Using these technologies we modeled campus scene one by one with the help of Creator, optimized these models with edge collapse technique, and then integration all of the scenes.2. Billboard technique, namely using tree image instead of tree is a common method in virtual scene generated by Creator, but in the close shot, tree image would give poor effect. This paper modeled trees that has vivid effect with fractal method, and combines the tree's fractal model with image model using LOD technology. By this approach, we preliminary realized the high-speed visualization and vivid effect.3. Completed an automatic roaming and a free roaming system, and add the collision detection in them, realized campus real-time roaming. The roaming system implies viewpoint forward, backward, left or right translate, left or right orate, weather variety and the on/off control function of background music, all of these supply better interactivity for the roaming system.4. Using progressive mesh simplification algorithm as a method to generate continuous LOD models, and controlling the scene complexity by providing different LODs, we improved the efficiency of the scene rendering and roaming systems realistic.5. Studied the particle system which describes irregular objects, simplified it. By controlling the particle formation, activities, death process, realized rain and snow effect in the roaming system.