Study And Implement About The Efficiently Rendering Of Dynamic Clouds

Modeling and rendering the natural phenomena is an important field in the virtual reality technology in recent years, and the study of simulation and visualization of clouds is a difficult and important area. It is difficult to describe the complex object which is changed irregularly with time. In this paper, we study the simulation of clouds from the modeling method, lighting model and the rendering efficiency.As far as the modeling method, we analyzed some other methods in the present time including particle system technology, fractal method and coupled map lattice method. Based on these methods, we present a new modeling method which unifies the Coupled Map Lattice method and the particle system method. This reduces the complexity of the simulation and make the real-time rendering become possible.The correct optical model determines the reality of cloud simulation. We introduced the important source-attenuation model and analyzed the single-scattering model and the multiple- scattering model. We present a new simpler formula for the lighting model based on the analysis of the cloud's optics property and the single scattering model to simulate the multiple-scattering method.Rendering realistic cloud images is a challenging task. The high computational demand makes physics-based rendering impossible for real-time applications on low-cost workstation. In this article, we also improved the rendering efficiency of the cloud by used the pre-fetch technology, LOD technology, stoppage ahead technology, the space segmentation technology and etc. A method which keeps a dynamic texture set of cloud particle in the main memory is put forwarded, aiming at reducing the rapid increasing requirement in the dynamic load texture method. We also study the re-use of the particle texture based on LOD technology and put forward a simplified method which decrease the number of rendering particle. The use of space segmentation technology and binary space partitioning tree for speeding up cloud rendering facilitates back-to-front traversal and hierarchical texture selection. We also applied the multi-pass rendering technology and stoppage ahead method to the cloud simulation. And we also used the alpha-blending billboard textures and multithreading technology.We design and implement a dynamic cloud simulation system and the inter-interface is designed according to the meteorology criterion. And we also validate the parameters that the...