Research On Photorealistic Rendering Algorithm Of Bubble Generation And Movement In Water

With the continuous development of computer graphics in fluid simulation,fluid animation has become more and more colorful.At the same time,people are increasingly interested in the simulation of common fluid phenomena in life.Whether considering bubbles entrained by splashing water droplets or boiling water,the presence of bubbles makes fluid simulations more vivid.However,bubbles are often ignored in practical fluid simulations due to their high computational cost.Bubble simulation is carried out based on the method of NS equation,and the research focuses on the complexity and realism of its calculation.First,in terms of reducing the complexity of the calculation,on the basis of satisfying the equation of motion of the momentum conservation of incompressible fluids,based on the standard pressure projection,the bubble incompressibility constraint is used as the boundary condition,so as to establish a simplified model that ignores the velocity change inside the bubble,saving computing costs.At the same time,in the particle neighborhood search stage,the space division method is used to separate the space where the particles to be retrieved exist in the form of equidistant grids,and only the distance between itself and the particles contained in the adjacent divided areas is calculated,so that the calculation time is greatly reduced.Reduced to make the neighborhood search more efficient.Secondly,in terms of enhancing the sense of reality,the viscosity coefficient is simplified as a constant and extracted in the divergence calculation,so as to achieve the effect of correctly representing the oscillating deformation of the surface of the bubble in the low-viscosity liquid;and generate implicit incompressibility according to FLIP particle interpolation.By solving the Poisson equation of the SPH particle,the pressure re-projection is completed to achieve the purpose of volume correction,which makes the simulation effect of bubbles more realistic and natural.Thirdly,in the rendering of underwater bubbles,by applying the bidirectional scattering distribution function in the shading model and setting priorities on different shaders,the rendering of transparent materials is completed,and the light is correctly reflected in different media such as air and liquid.Refraction at different boundaries between.Finally,using C++ language and Houdini engine platform,a series of simulation experiments are designed to simulate the process of bubble movement under water,and the realization of the simplified model of constrained bubble is verified.Experiments show that the method in this paper can present the simulation effect of water bubbles with rich details and realistic feeling.