Several Key Technologies To Quickly Build Realistic Scene Of The Three-Dimensional Virtual Simulation Earth

Currently, The Three-Dimensional Virtual Earth Technology and Virtual Reality Technology (i.e. Three-Dimension Virtual Simulation Technology)are developing rapidly and have made considerable progress and improvement in their respective areas. With the rapid development of relevant technologies, the urgent demand of applying the two technologies simultaneously was generated. Although current technical platforms are endeavoring to support not only 3D virtual globe, but also 3D virtual simulation, they are still in the level of loosely coupled integration with the 3D virtual platform having a weak function in virtual simulation and vice versa, while lack cross-sectional study in the underlying implementation technology. In this context, if the 3D virtual globe software is chosen, the needs of 3D simulation will not be able to meet and it works in the other way around, which greatly affects the promotion prospect of the relevant technical platform.In view of the above problem, in this paper, we proposed a scheme, which implements a deep cross-functional integration between 3D virtual reality technology and 3D virtual simulation technology. The scheme enables to construct a highly professional platform which was named 3D virtual simulation globe system. It densely combines 3D virtual earth technology and 3D virtual simulation technology. According to the expected scheme, the system should include spatial information processing system, GIS system, rendering system, object system, animation system, sound system, physical system, artificial intelligence system, communication system, scripting system, interactive system, behavior system, and other extended systems.etc.. due to the length, In terms of the complex structure of the system, this paper, taking the rapid construction of virtual 3D earth simulation scene and realistic rendering as the key entry point, systematically studied the key issues of basic simulation scene, the realistic simulation rendering, the automatic modeling of linear features, the rapid construction of the fine surface, real water, atmospheric environment simulation and so on.The contributions of this paper are as follows:In the research of basic construction of simulation scene, this paper firstly puts forward a hybrid separation method based on quadtree, octree and BSP tree for the purpose of managing 3D Virtual Earth scenes and the details of the different contents in simulation scene comprehensively. Secondly, we discuss Global topography data organization, scheduling, modeling and rendering method based on linear quadtree. Finally, based on topography scheduling mechanism we discuss the global large-scale 3D model data organization, scheduling method and extend this method to all point features.In the research of realistic simulation research, we mainly tries to increase the image fidelity combining several new 3D computer graphics theories and technologies, including BRDF illumination model based on physical rendering, SSAO theory and implementation, delay rendering theory and implementation, HDR theory and Implementation.In the research of online automatic modeling, firstly we study the general modeling method of the linear geographic features, such as piping, walls, etc. Secondly, the automatic modeling method of 3D road is studied because the road is the most important feature in 3D virtual scene. At the end of this chapter, the paper discusses the organization and management of the large scale linear elements and the method of directly generating linear geographic features from GIS data.In the rapid construction of fine surface research, we mainly study the fast rendering of surface details, rapid changes and smooth of terrain elevation, fast deletion and efficiency optimization of surface covering material (e.g. forest, grass, gravel) based on the problem of how to rapidly construct the fine and genuine surface environment.In the research of real water and atmospheric environment simulation, this paper firstly proposed the method of simulating the construction of river surface by employing real hydrological data, including real water level, flow velocity, flow direction and water level. Secondly, we studied the method of simulating atmospheric environment by using real weather forecast model data, such as 3D cloud, typhoon, haze and so on. The 3D simulation result shows that the 3D visual fidelity constructed based on the real data is high, can be regarded as a visualization of professional data and it plays an important role in application.