Distributed Terrain Rendering

With the development of computer and virtual reality technology in recent years, The applications of 3D scene , especially of large-scale massive terrain data rendering, are required more and more. But the process ability of computer hardware at present can not satisfy the demand of massive terrain data rendering at real time at all, mainly including two problem: (1) process speed can hardly meet the needs of real-time. (2) the resolution of scene can hardly meet the needs of larege-scale 3D scene walkthrough ,for examples, such as PowerWall,IDesk ,CAVE system.Aiming at the above problems, they are tried to resolve from two aspects in the essay: (1) reducing the quantities of data processing, making use of grid reduction technology to simplify scene data; (2) breaking through the lack of computing ability and resolution in the environment of single computer, utilizing computing and graphic rendering abilities.Not only Correlative technologies of terrain display,visual algorithms in virtual reality and algorithms of terrain simplification are discussed in the essay, but also 3D terrain visualization in the distributed environment is analyzed. Being dead against the shortage of traditional terrain visualization algorithms, they are improved from the following two aspects in emphasis:(1) realized a dynamical LOD simplification algorithm on the basis of dependent of view. In the traditional LOD algorithms of dividing the terrain based on levels, there is hopping between different levels of LOD, and the cracks between different levels of LOD can hardly be erased. Dynamical continuous morphing between different levels of LOD is realized , through the relationship between vertices to avoid cracks.(2) Assigning the whole scene display tasks to several different computers, adopting the assignment algorithm based on image division with the strong computing resource in the distributed environment, which processing result is outputted directly from local computer and displayed on the PowerWall projection system, coming into being a whole integrated scene.