Research On The Technology Of LOD In Virtual Reality

Virtual reality (VR) applications, computer-aided design (CAD) applications and scientific visualizations often need user-steered interactive displays of very complex polygonal environments, for which, however, the computation and storage requirements far exceeds the capacity of modem graphics hardware. Levels of detail (LOD) representations are an important tool for real-time rendering of such environments. This thesis contributes to the dynamic generation and rendering of models at multiple level of detail (LOD) used in real-time graphics rendering.In Chapter 1, we describe the basic concepts and primary characteristics of VR systems, then present the methods for accelerating graphics rendering in VR.The related research works, research contents and importance associated with LOD models are also described in chapter 2. This chapter optimized the algorithm provided by Michael Garland and Paul S.heckbert based on edge contraction, and the improved algorithm can produce better approximation.A new method provided to simplify triangulated model with appearance attributes, and optimized the method to reduce the complexity in chapter 3. The dissertation advances a new concept: Density of Meshes, and study the applications of density of meshes in discrete multi-resolution and continuous multi-resolution.In chapter 4, a new method is presented for implementing the BSP tree. The future work is offered in Chapter 5, it includes the compact of data, view independence and the rendering of model with both discrete multi-resolution and continuous multi-resolution.