Research And Implementation Of Creating 3D Terrain

The technique of 3D(three-dimensional) terrain generation is the key technique inthe virtual digital environment construction,where scene reality,multi-resolution andattribute query ability on terrain model are desired.This dissertation is based on China"863"project. According to character of real-time,accuracy and reality in the terrain ofspace launch site,researches creating technology and modeling method of 3D terrainwith MultiGen Creator platform.Bring forward an effective application project for 3Dterrain generation.Generates a 3D terrain of space launch site with perfect visual effect,and the terrain has been applied to the 3D simulation system.Firstly,researches creating technology for 3D terrain. Discuss DEM from someaspect in data obtainment.Mainly introduces the principle of projection transformationand geometry projection classification in DEM projection transformation.Researchesthe predigestion methods of TIN model and DEM model in predigestion technology.Researching texture mapping and illumination meets for the character of reality.And theLOD technology meets for the character of real-time.Secondly, researches the methods of 3D terrain modeling.Analyzes RTN, TRN,TIN and Delaunay Triangulation theory.form and mixing model method.Comparingwith them from complexity,applicability,data and detail aspects,draw an conclusion.Mixing modeling method combines the merit and improve deficiency.So,it excels to theothers methods.Next,adopts MultiGen Creator with creating technology and modeling method of3D terrain.Put forward an new source data of terrain(grid map) conversion method.Sumup paste texture with contour strip.And put forward an method of combiningPolymesh/Irregular Mesh algorithm with sampling mesh predigestionalgorithm.Including above all,choosing projection method and ellipsoid,settingLOD,bring forward an effective 3D terrain application project.Finally,According to the terrain of space launch site, generates a 3D terrain withperfect visual effect, and the terrain has been applied to the 3D simulation system.