风场作用下的动态森林场景的实时仿真

为真实地模拟树在风中摇曳的动态效果,将风场视为一个随机过程(场),利用谱分析的方法生成给定条件下的风速矢量场;进而采用简化的动力学方程,实时计算风力作用下树的位移和形变.采用一种混合式几何和图像的表示方法对树木进行参数化建模,并在模型中内建多个细节层次,以便加速场景视点相关的绘制.综合以上算法的交互式漫游系统能实时地模拟包含数千棵树的森林场景在风场作用下的动态效果,初步满足了虚拟现实、战场仿真与数字娱乐等应用的要求.

Real-time Simulation of Dynamic Forest Scene in the Wind

Real-time rendering and interactive simulation of dynamic forest scenes remain a challenging issue in computer graphics. In this paper, we propose a physically-based scheme for the simulation of dynamic forest in the wind in real-time. We model the natural wind as a stationary stochastic process/field adhering to the principles of Wind Engineering and generate it by power spectrum analysis and synthesis. To reduce the computation and memory consumption, we adopt a hybrid geometry-image representation to model the appearance and geometry of trees faithfully and efficiently. We achieve the motion of trees driven by the wind force using simplified dynamical equations, which guarantees visual plausibility. In addition, three types of LOD are exploited to improve the performance of the whole scene, by adapting the complexity of tree model, motion of branches and the wind field according to visual importance in these aspects. Finally, we simulate a middle-scale forest scene containing thousands of animated trees by our approaches. The result demonstrates that the proposed scheme is effective and practical for the interactive applications such as VR and videogames.