Research On Key Techniques Of3D Terrain Generation

Virtual reality technology, through the simulation of the real natural environment, canshow a realistic virtual digital environment in the computer, it can be applied in entertainment,education, training, etc. Virtual reality technology simulation application requires not only thevisualization system with high sense of reality, but also good real-time ability, and thus toenable the participants to immerse in a virtual digital environment. A3D terrain is animportant component of the virtual digital environment; it directly influences the sense ofreality of the virtual environment. As the increasing demand for the data size and precision ofthe3D terrain, the existing ordinary computer hardware conditions become the bottleneck oflarge-scale3D terrain visualization. This paper based on multi-resolution terrain modelgeneration method, systematically studies the key techniques of large-scale3D terraingeneration and visualization. The main work is as follows:On the basis of terrain elevation data, study the multi-resolution terrain model generationtechnology based on regular grid. The time space continuity solutions of the3D terrain havebeen given, to solve the cracks and sudden jump problems when drawing the multi-resolutionterrain model; we introduce terrain feature attribute factor into the traditional terrainevaluation criteria, so as to maximally simplified terrain mesh under the premise of reservingnecessary details feature of terrain; meanwhile using vision field clipping scheme to eliminatea large amount of redundant terrain data, and improve the efficiency of scene drawing.To solve the problem that restricting large-scale terrain data loaded into memory, thelarge-scale terrain data partitioning management and scheduling plan have been put forward.The principle of large-scale terrain data management has been formulated, and the scheme ofpartitioning management has been presented to organize the huge amount of terrain data; theterrain data anew organization is established based on the logical block, which can ensure thelocal continuity of terrain data memory space; the data prediction scheme is given based onexpansion cone; the prefetching scheduling and scene drawing for large-scale terrain dataunder the mode of double thread are realized, the utilization of the system memory isimproved effectively.In order to improve the realism of the visualization scene, the multi-resolution texture mapping scheme based on quad-tree structure is put forward. Based on texture concept, theoriginal terrain texture is processed into the multilevel texture, and divide all levels of textureaccording to the quad-tree structure, according to the terrain quad-tree nodes of real-timerendering, obtain their corresponding texture data to mapping; the texture data prefetchingand scheduling strategy which is based on the cache is proposed, to accelerate the texture datascheduling speed.Finally in order to verify the feasibility of the terrain generation method based onmulti-resolution, integrate the key techniques of terrain generation and visualization tovisualization system, and realize interactive roaming of large-scale terrain. Experimentalresults show that the visualization system has a good sense of reality and real-timeinteractivity.