Research On 3D Simulation Algorithm Of Large-Scale Cloud Data Based On WRF Model

Simulation of natural scenes in the real world has always been one of the most important research in computer graphics.As one common natural phenomenon,cloud has a variety of shapes and the propagation of light,which makes the three-dimensional simulation of cloud become one of the most challenging tasks in the field of computer graphics.At present,the simulation of three-dimensional clouds is mainly divided into phenomenological method and physics-based method.The former does not take the physical meaning of clouds into account,so the generated clouds look realistic but without meaning of meteorology.The latter takes accurately into account aerodynamic,hydrodynamics,and thermodynamic information to produce one more realistic cloud simulation,but the speed of large-scale simulation is limited by a large number of calculations and cannot be applied in real time.Therefore,the 3D simulation of large-scale clouds has the following problems to be solved urgently: 1)Only pursue the visual effect of 3D cloud simulation ignoring the physical meaning of clouds,especially their value in meteorology;2)The 3D model of cloud is constructed by complex physical equation,which requires too much computation to realize real-time interaction with users.In view of the above problems,this paper studies large-scale cloud 3D simulation based on WRF mode.The main research work of this paper is as follows:(1)In the aspect of modeling,the paper analyzes the current mainstream modeling algorithm,the particle system method based on the level of detail is proposed.On the basis of the traditional particle system,the WRF data is combined with.Technically,through the optical depth and extinction coefficient,the distribution strategy of the particles within the grid is set,then the correlation surface is introduced,the clouds are seen as the hierarchy structure of interconnected relationship.The correlation between particle properties is set up,and the level of detail technology is introduced to establish the relationship between the level of detail and the visual range,particle radius and number.The simplification of the number of particles in the cloud simulation process accelerated the rendering speed through experimental verification.(2)In terms of cloud illumination rendering,the commonly used illumination models are analyzed and compared with.Aiming at the complexity of illumination model implementation and low rendering efficiency in the process of 3D cloud simulation,a method based on precalculation is proposed to calculate the internal light depth,single scattering and multiple scattering of reference particles.Light depth,single and multiple scatters for each position,direction,and light are calculated and stored in a lookup table.At runtime,information in the table is used directly;In addition,an improved particle mixing method is proposed for the light interaction among particles,which can produce more accurate color mixing by considering the intersection of volumes.Experimental results show that this method can improve the rendering speed and eliminate time artifacts.