The Visual Research About 3D Terrain And Physiognomy

Virtual reality is a virtual world, which created by users in computers. This world can exchange actions with users. And its foundations come from the real world or the imagenation about our furture lives. Using this technique, we can generate the 3D terrain sences to reflect the real terrain of our world. Comparing with the tranditional maps, this sences have lots of adventages, such as visualization, easily storage and query , in time created. Therefore, its have immensity using values in various areas.Firstly, I review the history of the technology of virtual reality and terrain simulation, briefly introduce the details of the virtual reality and terrain simulation, which includes the background, the basic concepts, basic principles, characteristics, applications, classification and the classical algorithms in the virtual reality and terrain simulation. Secondly, I stress on the representative algorithms in the terrain simulation, the existed problems and mainly countermeasures. Finally,combine with the ChuenHui program of Ministry of Education——"The Basic Research aboutDigital Museum of Karst Topography Based on Girding Technology", I put forward the terrain and liquid generation algorithms which based on grid data, realize the corresponding 3D cruise system and leave each other performance evaluation and testing.In this paper, I mainly stress on two terrain simulation algorithms and two liquid simulation algorithms. The terrain simulation algorithms, one is based on Quartree organization; the other is based on Octree organization. The liquid simulation algorithms, one is abnormity natural phenomena simulation based on particle system, the other is dynamic mutual simulation between liquid and floater that based on 2D wave equation. Using this algorithms and combine with the mixing texture mapping technique, shadow rendering technique, I realize the s nulation about natural terrain and generate the large realistic 3D terrain scenes. Finally, the 3D cruise systems are built which include the collision detection of user movements is realized in these scenes. Some experiments are tested on this system to judge the performance and capability of them. The results of these experiments indicate that these simulation schemes are not only having excellent simulation about terrain and physiognomy, but also can realize the dynamic detection with users during cruise in the scenes. This system possess preferable characteristics which should be included in the ideal VR system ,they are immersive,interactive and autonomy.The first chapter is the introduction. In this section, I mainly introduce the investigation background and the learning purports about this problem. I summarize the ideas about modeling and the simulation in 3D terrain, analyze the status of this problem and point out the real weak points in this phase. Finally, I bring forward to the main contents of this paper.In the second chapter, I particularly talk about the virtual reality technique and it's realization platform. Firstly, I introduce the basic conception, the mainly characters, and the progress situations about virtual reality. Secondly, I focus on some development tools about virtual reality, such as OpenGL, Java3D, Direct3D, VRML, to analyze them weak points and strong points. Finally, I describe how to use OpenGL to build the virtual reality development platform.The third chapter particularly talks about the terrain simulation. I introduce the basic conception, the realization process and the setting about the terrain simulation. And the terrain simulation techniques also are analyzed. This section introduce the basic process that how to use...