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In recent years, fluid simulation under a virtual scene has been widely used in various fields such as computer games, the film and television advertisement, electronic game. Fluid phenomenon mainly includes flow, smoke, bubble, cloud, flame, explosion, waves, spray, etc. Although fluid phenomenon looks simple and ordinary, it has no definite shape, and it is difficult to use modeling method to express, so it is highly complex and difficult to simulate real fluid. This makes the fluid simulation become a difficult and hot topic of research of computer graphics.Early fluid simulation, the non-physical method is used to simulate the surface or wavy, for calculating ability is bad, this kind of method is often difficult to control and shall not applicable for some complex phenomenon. In the 1990s, physical based method has been introduced into the computer graphics, which is mainly based on Navier-Stokes equation of fluid dynamics. According to description of fluid, the different methods can be classified into Lagrange method and the Euler method.The main contribution and innovation of this thesis are summarized as follows:1. This article uses SPH (Smoothed Particle Hydrodynamics) method to simulate the fluid, which is a gradually developed method in nearly 20 years. The basic idea of SPH, the solving process of Navier-Stokes equation using SPH method and the design of kernel function are given in detail in this paper.2. In view of deficiencies of previous Particle System rendering methods in fluid simulation, a special-effect rendering method with separated physical model was proposed,which was guided by the idea of mapping the alpha-value-attached texture to particle. Different from previous texture mapping methods, the shape of non-transparent patterns in texture was only used to determine the shape of particle, while the color and size of particle were changeable. By this kind of texture mapping, the fluid shape could be better manifested, and the real-time changes of fluid density could be reflected by the time-varied color and size of particles.3. Based on the solution of Smoothed Particle Hydrodynamics Model, clouds of smoke and flow rolling effects were simulated by this rendering method. And in the replacement of a physical model, seabed bubbles and submarine tail wave effects were simulated using this method. Results show the advantages of this proposed method in effectiveness, real time, simulation fidelity and universality.
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