交互式水滴效果模拟

摘要

为了有效地模拟小水团受重力和人为外力的影响而散开为动态水滴的现象,提出一种水滴效果的交互式模拟方法.首先采用精确SPH模型模拟小比例的水滴现象,通过精确地计算压强力及人工速度场校正来保证流体方程求解的精确性、稳定性及收敛性；然后根据流体密度场提出一种基于平均曲率的表面张力模型,能够有效地模拟水滴的表面张力现象；最后基于新一代着色器模型提出一种适用于水滴渲染的光线追踪方法,包括简化的流体密度分布、基于二分法的流体等值表面判断和基于菲涅尔定律的光学特性计算,克服了传统流体渲染独立于摄像机、计算量大等缺点.实验结果表明,文中方法是有效及高效的,可以同时适用于水体现象及小比例水滴现象的模拟.%In order to effectively simulate the phenomenon of dynamic water drops with gravity and other external forces,this paper presents an interactive simulation method for water drop effects.Firstly,an accurate SPH model is taken to simulate small-scale water drop phenomenon.The method includes accurate pressure strength calculation and artificial velocity field correction,to ensure the accuracy,stability and convergence of fluid equations.Secondly,a surface tension model is presented based on mean curvature and fluid density field,for efficiently simulating the surface tension of water drops.Finally,a simplified ray-tracing method based on a new shader model is presented,for the water drop rendering.The ray-tracing method includes simplified fluid density distribution function,fluid surface judgment based on dichotomy and Fresnel calculation,for overcoming the problems in the traditional fluid rendering method,with little consideration of cameras and intensive calculations.The results show that the new algorithm is effective and efficient,suitable to the simulation of both water body and small-scale water drops.