Dynamic Conversion Of TIN To GRID-Based On The Quadtree Multi-resolution Display And Real-time Rendering

3D terrain as a basis for building a virtual environment has been widely applied in related fields.However, the amount of three-dimensional terrain data is often very large, at least up to tens of megabytesof data of the corresponding model in the terrain of the general large amount of data. Therefore, how tostore terrain model and draw a large amount of data has become a bottleneck in the terrain modeling. Inrecent years, in order to reduce the amount of data of the terrain model, terrain model to simplify themulti-resolution terrain modeling, terrain model LOD technology and the algorithm were applied.Simplified three-dimens ional terrain data modeling and model for the current status quo around theregular grid and irregular grid terrain digital model, terrain model simplification,and the terrain multi-resolution model and other key technical content of discussions and research.Regular grid terrain by means of the advantages of the grid structure often can be applied to quadtree-based LOD algorithm[1,2]and efficiently select the LOD triangulation and real-time rendering.Rule-based grid QuadTree LOD algorithm in a large number of theoretical and practical has been proved tobe very efficient, its main advantage embodied in the can quickly LOD selection and triangulation, themain disadvantage is that there are a lot of data redundancy (the same amount of data in flat regions andalpine areas), and its adaptability is restricted because of their structure. Simplified based on triangulatedirregular network segmentation method applicable to any irregular sampling points set, and can be withinthe limit error threshold, with less triangles can accurately express the terrain. Triangulated irregularnetwork structure, however, the LOD is not much reason, the data is the data structure of the discrete dataand the complex structure is not a rule, there is a big difficulty as well as simplify and breakdown ofoperating, but also in building need a more complex hierarchy and relatively larger memory overhead.Therefore, using the advantage of the GRID terrain on the structure and TIN on the number of verticesin the expression of the terrain advantage, the LOD of the terrain model generation algorithm, and focuseson the multiple levels of detail LOD algorithm based on the TIN model, and explore for GRID modelQuadTree-based LOD algorithm, the final design of the QuadTree-based LOD algorithm for the TINmodel.