Some Researches On 3D Water Simulation

Fluid simulation is an important branch of computer graphics, which has been widely used in lots of areas, such as the special effects in film and television, military simulation, animation and medical area etc. How to find more efficient models to simulate real fluid more rapidly and effectively is meaningful and very impotent.Chapter 1 mainly introduces the histories, backgrounds, research significance and status at home and abroad of the fluid simulation, and states the main work of this thesis.Chapter 2 introduces the SPH method and PBF method, analyzes the difference between the two methods. Besides, a surface reconstruction method——Marching Cubes algorithm is introduced.Chapter 3 constructs three modified models of the PBF method to speed up the fluid simulation and improve the simulation effect:density constraint model, velocity classification model and position layering model. Because of the incompressibility of the fluid, the density constraint model can make the density of the fluid tend to stable by adjusting the position of particles. Besides, this model introduces a parameter to solve the problem of the inaccuracy due to uniform distribution of particles near boundary. The velocity classification model divides particles into three types according to their velocity:active particles which calculation accuracy is high and ask more iterations, ordinary articles which calculation accuracy is average and ask medium iterations, and inactive particles which calculation precision is low and ask less iterations. This classification can speed up the fluid simulation. The position layering model divides particles into three types according to their positions:small size particles at surface area of the fluid which are used to improve the surface simulation effect, middle size particles in middle area of the fluid and big size particles at bottom area of the fluid which are used to accelerate the fluid simulation. In this model, a new fusion-separation technique is given and the buoyant force is taken into account to make the model more stable and get better simulation result.In chapter 4, the modified models given in chapter 3 are implemented by VC++ language and OpenGL graphics library; the simulation results between the PBF model and the above modified models are compared and analyzed.Chapter 5 gives a summary of this thesis and some thinking and outlook of the future research of fluid simulation.