Three-dimensional Flame Real-time Rendering Method Research Based On Physical Model

With the rapid development of computer hardware and popularization of the internettechnology, the rapid development of movie special effects and electronic games, constantpursuit of the public on exquisite picture and the vivid images, there is an urgent need to improvethe speed of computer simulation, the simulation of the natural landscape is the one of theimportant simulation, in recent years, the natural landscape simulationhas become one of the hottest spots of the computer graphics, the flame simulation has attractedmany researchers’attention. they can be used in movie special effects、video games、and advertising industries，which had a huge social and economic benefits. with the continuousdevelopment of computer technology and fluid dynamics, the flame simulation technology isalso in the unceasing development and progress based on the flame generated by the traditionalparticle, generally can meet the flame shape, in general very fast, but has great randomness, moreparticle, much slower, the flame generate by texture techniques is roughly in linewith the shape of the flame, less computation. the calculation process is relativelysimple, basically in line with the scene of the burning, but there are traces of artificially drawn.therefore, the flame simulation algorithm research has important practical significance. this papersummarized the flame rendering of the various research methods as well as at home and abroadin recent years based on the physical model of flame rendering research trend on the basis of,using a physical model based on the real-time rendering method of flame.The main research goal is the improvement of the algorithm based on the physical model,which is proposed and implemented faster ,based on the physical model algorithmsimulation, the more the man-machine interaction, renderings generated more realistic, which isto promote flame simulation technology to fast forward.This research work include the following three aspects:(1)This paper analyzes the background and significance of the flame simulation technology,and summarizes the existing fire simulation algorithm, and proposes the direction ofdevelopment of the flame simulation algorithm at this stage. this article summarize theadvantages and disadvantages the existing algorithms based on particle systems, texture systemsand physical model,inorderto furtherimprove the flame simulation algorithm ,which provides theoretical support.(2)The paper describes the finite difference method, finite element method, the finite volume method, and compared the advantages and disadvantages of the three kinds of numericalsolutions, decided to use the finite difference method for solving the Navier-Stokes equation,using Helmholtz-Hodge decomposition formula decomposing partial differential equations,partial differential equation is decomposed into several simple computation of equation, and thensolve the equation. using a Lagrange method for solving advection, guaranteeing the stability ofalgorithm, using characteristics of particle systems for modifying the advection equation ,usingthe implicit iterative methods for solving the diffusion equation, which can be in any step offlame simulation, finally get the equation solution sets together and obtain the final solution ofequation.(3)This paper introduces the overview of GPGPU, then introduces the overview of CUDA,in the process of calculation, because of the computer hardware GPU powerful parallelcomputation ability and high computing density, and the equation has the same operational stepsand independent from each other, so it is suitable for using GPU to do parallel computing, toaccelerate the simulation. finally, using Jacobi iterative method for solving linear equations,using ray casting algorithm rendering flame, ray casting algorithm for parallel computing, andray casting algorithm for parallel computing。the last ,generating the realistic flame images. theexperimental results show that the method is simple, rendering is fast and the process of thegeneration of rendering is true.