Large-scale Terrain Modeling And Dynamic Rendering Technology Research

With the present of digital-earth concept and comprehensive application of virtual reality technology, 3D terrain visualization technology, as an indispensable part of those ,is playing an more important role in daily life. Actually 3D terrain visualization employs the real terrain data(DEM grid)and high resolution satellite images. Thus such huge quantity of data prevent the real-time visualization of large-scale terrain. In order to solve this problem, researchers have done a lot of work. And most of these work concentrates on the creation of irregular triangle network and multiresolution terrain models .In this paper, a great deal of work has been done on the above two aspects to solve the problems concerning in the visualization part of NanNing Flooding Information System.This paper mainly discusses the following aspects: the creation method of irregular triangular network from regular grids, fast computing method of vertex normals in TINs, the creation method of multiresolution terrain models and method of view-dependent real-time rendering. The algorithm in this paper works efficiently at a lower error. In most applications it is impossible to realize the fast visualization and fly-through of terrain at a given accuracy.