摘要：

为增强实时三维雨天场景的真实感,提出一种模仿物体表面水滴运动的动画仿真方法。针对已有降维模拟方法中水滴无法离开纹理空间的问题,将水滴分为二维与三维2种类型,实现世界空间下的三维水滴与纹理空间内二维水滴的相互转换。物理仿真时将水滴视为刚体粒子, 通过基于velocity-verlet的积分方法求解运动轨迹方程。渲染时依据纹理空间内的仿真数据生成高度图,并根据高斯模糊与色阶算法模拟水滴间的液体桥现象,将其转换为法线纹理渲染水滴。实验结果表明,该方法能够实时模拟物体表面的水滴运动,使得降维水滴运动模拟 不再依赖于连续曲面,对比基于光滑粒子动力学的二维与三维模拟方法,模拟效率分别提高2倍与5倍以上。

关键词: 流体模拟, 水滴, 坐标空间转换, 法线贴图, 液体桥, 动画仿真

Abstract:

A method which can animate and simulate the movement of water drop on the surface of an object is put forward to enhance the realism of real-time 3D raining scene.The water drop can only move within the texture space in the existing dimensionality reduction simulation method,so it is divided into two types,which are 2D and 3D water drops,thus realizing the interconversion between the 3D water drop of the world space and the 2D water drop of the texture space.The water drop is regarded as a rigid particle when conducting physical simulation and its equation of movement locus is solved by velocity-verlet integration method.When it is rendered,a height map will be generated based on the simulation data in the texture space,then the liquid bridge phenomenon between the water drops will be simulated based on the Gaussian blur and color gradation algorithm,finally it will be converted to normal map for the rendering of water drops.Experimental results show that this method can simulate the movement of water drop on the surface of an object in real time,which makes dimensionality reduction simulation of the movement of water drop no longer depend on a continuous curved surface.The simulation efficiency of this method is improved by over two and five times respectively when comparing with the Smoothed Particle Hydrodynamics (SPH)-based 2D and 3D simulation method.

Key words: fluid simulation, water droplet, coordinate space conversion, normal map, liquid bridge, animation simulation

中图分类号: 

• TP391.9