中文摘要：

针对虚拟环境中大规模三维云渲染开销大的问题，提出一种大规模三维云实时模拟方法．在云建模方面，利用Navier-Stokes流体力学公式模拟云的动态生成，提出一种基于八叉树的模型化简策略，减少了云模型粒子数；在渲染阶段，提出一种基于Cell的绘制更新策略，结合Impostor技术自动混合绘制三维云与Impostor，实现了大规模三维云的实时模拟．实验结果表明，该方法基于物理的方法模拟云，同时在绘制阶段根据视点的移动实时更新，效果逼真；与同类方法相比，基于Cell的绘制策略更新时计算量更小，有效地避免r绘制更新时常见的抖动和跳变问题．

英文摘要：

According to the problem of time consuming on large-scale 3D clouds rendering in virtual environment, this paper presents a real-time simulation method for large-scale 3D clouds. In modeling process, the Navier-Stokes equations are adopted for cloud modeling, and a method based on octree is presented to reduce the particle number of the cloud model. In rendering process, impostor technique is used and a schedule algorithm based on Cell is proposed to render the mixed 3D clouds and impostor automatically. As the clouds are simulated by physical model and updated in real time when the view moves, the rendering effect is highly realistic. Compared with other works, our algorithm based on Cell schedule shows better efficiency on computation, and substantially improves the jerky phenomenon effectively.