基于物理的真实感流体模拟研究

【作者】 曹跃；

【导师】 李毅超；

【作者基本信息】 电子科技大学 ， 计算机应用技术， 2008， 硕士

【摘要】 计算机图形学是虚拟现实与数字媒体技术的核心。虚拟现实、电影特效以及电子游戏的强大需求,不仅推动着工业界不断提升图形处理硬件的性能,学术界也积极投身其中。然而在交互式高沉浸感的虚拟环境中,依然存在着诸多基础性的研究问题与挑战,其中逼真的实体运动模拟问题尤为突出。作为计算机图形学的一个分支,计算机动画是计算机图形学和艺术相结合的产物。在构建未来高沉浸感虚拟现实系统中,对计算机动画的研究将具有举足轻重的战略作用。因此,计算机动画始终处在研究的前沿,人们不仅需要静态形象的真实感,也需要运动的真实感。而真实运动的复杂度往往使得人们难以用一些过程表述,这个时候只有借助于真实世界的物理规律才能得以体现。基于物理的动画已成为计算机动画领域中的一个前沿研究热点。基于物理的动画模拟使得人们摆脱传统僵硬的“固定动画”成为可能,因此具有非常强的前瞻性。基于物理的计算机动画一方面使得本身体现的现象能充分满足人们对真实感的需要;另一方面减轻了程序开发人员和艺术家的劳动强度。本文以基于物理的计算机动画作为研究目标,对这一课题的研究着重集中在以下三个方面:第一,对基于物理的流体动画模拟算法作出了全面的研究和透彻的分析,在此基础上提炼出了真实感流体模拟的关键问题;第二,针对真实感流体模拟的核心问题,提出了基于物理的真实感流体动画模拟的改进算法;第三,实现了无网格流体动画模拟的算法,对算法的运行结果进行了充分的比较和分析,并就未来的研究热点进行了展望。本文算法的主要贡献和创新点在于如下工作:①在涉及流固耦合边界运动的模拟中,提出基于物理采样因子的多分辨率流体模型和真实感流固双向同步耦合模拟方案,解决了传统算法的异步误差问题;②针对热力学三态相变的模拟,提出基于流固包容模型的平滑相态转变算法,并设计出高适应性的粒子表面重构方法;③提出多分辨率流体物理模型的概念,针对不同尺度范围的流体动画采用不同的物理模拟方法,构建一个平滑过渡的流体动画模拟系统。更多还原

【Abstract】 Computer Graphics is the core of the Virtual Reality and Digital Media. Realistic modeling of natural phenomena has been a hotspot and one of the most difficult tasks in Compute Graphics. It has been found wide application in many domains such as computer animation, landscaping, architecture, special effects of movie, computer games, battlefield simulation and virtual reality, etc. Physically based modeling must be applied to attain more realistic results on both shapes and movements, on the other hand, the simplification and acceleration techniques also should be introduced to render the dynamic and whole effects of natural phenomena more quickly. So the physically based modeling aims to seek for a tradeoff between the realistic effects and real time performance, to meet the needs from various applications.Physically based computer animation is always a hot topic in computer graphics especially in the special effects industry for films and games. Only physics makes the virtual scene more realistic, and takes the easy way out of the complex problems for simulation which gives the developers and artists more and more dream space.This thesis focuses on the study in three aspects, including research and analysis of physically based fluid simulation algorithms, so as to make sure the key problems in realistic fluid animation; design the advanced methods for fluid simulation, which aim at the immediate problems; implement the meshless fluid simulation algorithms, alsocompare the results for conclusion and future works.The main contributions of this thesis are mainly in the following aspects:①To make sure stability and nicety in fluid simulation, we attempt on adaptively sampled multi-resolution particle fluid model based on physics and geometry sampling factors, with realistic fluid-solid two way synchronous coupling algorithms in the simulation;②Use phase transition model with fluid and solid co-exit, with the adaptive surface re-construction method for fluid particles, we can simulation three phases transition realistically;③Consider the microcosmic physics model for the attachment and penetration of small liquids, we attempt on multi-resolution physics model for large and small scales liquid simulation, with a middle transitional model, so as to build a integrated liquid animation method.更多还原