Research On The Simulation Method Of Fluid Analogues In Three-dimensional Graphics Engine

The fluid simulation method in the3D graphics engine has been the focus ofdomestic and foreign research institutions. In recent years, a large number of researcherscontinue to propose new solutions for such simulation problems in motion modeling,behavioral modeling, rendering methods, etc. It makes this type of simulation methodsto promote in many applications, including Military Situation, Simulation Training,Disaster Response, Urban Simulation, and Exhibition.To meet the needs of various types of three-dimensional graphics applications andsimulations, this dissertation based on the Navier-Stokes equations, made an in-depthstudy of several key technologies, such as Real-time Crowd Behavior Simulation, theFast Particle Dynamics and Large-scale Cloud Simulation Based on the Aerodynamics.Main contributions of this dissertation include:(1) To solve the problem of level of detail for a large-scale crowd behaviors, aprogressive-level model of large crowd has been proposed, which combines fluiddynamics with autonomous agents and achieves a smooth transition between the twotechnologies. Based on the Euler form of the Navier-Stokes equations and the continuityequation, several problems of crowd simulation have been solved, including constraints,path planning, and dynamics simulation. An efficient rendering method of mixed GLODand Impostors is proposed, which adopts multiple representations of the role model indifferent observation distances, and effectively reduces the polygon number of real-timerendering.(2) Based on the smoothed particle hydrodynamics equations, a detailednumerical analysis is given for the calculation of density and force fields, and anadvisable choice of smooth kernels is made to meet the needs of Compact Support andnormalizable kernel. A neighbor query method based on spatial hashing is presented,which greatly improves the query efficiency of the tens of thousands of particles,without the maintenance of global spatial information. A fast surface reconstructionmethod based on the vertex deformation is realized. It extracts the fluid surface usingvertex deformation of the predefined geometry, and it is several times faster than the traditional Marching Cube.(3) A Three-dimensional cloud simulation method is proposed based on theprinciple of aerodynamics improved. The close-range rendering of cloud particles basedon elemental textures and the distance rendering using Impostors of the regular octagonring are proposed, which improves the speed when rendering a wide range of cloud,reaches the target to reduce the number of polygons, accelerate draw. A simplifiedillumination model of cloud is presented based on the atmospheric scattering, whichcalculates single scattering light model on the single particle, and greatly reduces thecalculations of cloud particles lighting. Effective solutions are given for the cloudsimulation in experiments and applications, such as cirrus modeling,"hard lines"problems of in-clouds experience; cloud flowing effect, coloring and shading process,clouds halo; simulations of smoke, fog and battlefield explosion.