Fast and Realistic Simulation for Trees Swaying in Wind
You Liu · Chinese Journal of Computers · 2005
Fast and realistically simulating the tree swaying in wind is still a challenge topic in computer graphics. For the existing methods, some are slow for deformation computation and some can handle only simple tree models, which is difficult to achieve high realistic impression for the tree swaying in wind. This paper presents a new method emphasizing on accelerating the computation for the physically based deformation of the complex tree model so that the tree swaying in wind can be simulated in high efficiency. On the one hand, it employs a wind model based on the real wind law through the Gauss distribution so that the turbulent effect on the tree can be fast computed. On the other hand, it speeds up the deformation computation for the whole tree by first calculating its branch deformation respectively and then assembling the deformation of the branches based on the links between them. To fast compute the branch deformation, the non-end branch with little amplitude is analyzed statically to deform, while the end branch is deformed by solving its dynamic response with the Newmark step-wise integration method. In rendering, the new method takes full advantages of the hardware-based shadow mapping and level-of-details (LOD) techniques for fast producing the realistic images of the tree. Experimental results show that the new method can fast and realistically simulate the tree swaying in wind for a complex willow model in nearly 40 thousand control nodes and 09 million triangles.