The Research Of LOD Technique And Its Applications

Along with the progresses made in 3D modeling technology, the object models in virtual environments are getting more and more complicated and the whole scene usually overloads the capabilities of graphics chips. Level-of-Detail (LOD) technology loads appropriate models for objects in the scene according to their visual importance. It can optimize triangle distribution of the scene and has become a key technology of the real-time rendering.The main interest of this dissertation is the auto-creation technology of simplified model. The emphases are put on the Vertex-Removal based LOD and the Triangle-Removal based LOD. And simplification experiments of models in virtual environment are listed. The main contents and results of research are shown as follow:The Vertex-Removal based LOD is studied. The judgment algorithm of Ordinal-Vertex-Loop and Vertex-classify algorithm are discussed in detail, and the local hole created in simplification is triangulated by Delaunay triangulation technology.The Triangle-Removal based LOD is studied, which includes a curvature-weight based LOD and a distance-weight based LOD. Furthermore, triangle constriction based LOD, which is a novel simplification method, is discussed in detail.The OpenFlight file format and OpenFlight API are introduced briefly. The data structure for this project is designed. Examples of simplification results are given and some ideas about future work are proposed.Experimental results confirm that the LOD technologies discussed in this dissertation are effective. And we can see that this project made a good preparation for the study of advanced LOD technology and the rendering technology of complex scene in the future.