Research Of Three-Dimensional Modeling And Visualization Technology On Clouds

Cloud,as one of the common phenomena of nature,is one of the important signs of the weather forecast,its shape,distribution and movement can effectively reflect the movement,stability,and water vapor content of the atmosphere,so it is very important to analyze the data and information of clouds.However,as the cloud data include amount of information and its source is wide,it is not practical to deal with the data directly and the workload is huge,so it need to convert the relevant cloud data to corresponding graphics,and then pick up the distribution and movement law of cloud.Three-dimensional modeling and visualization technology is a new computer technology developed recently,which is interdisciplinary and comprehensive.Its purpose is to express the three-dimensional model of simulation object with computer graphics,image representation and structure information,et al.To create a realistic,interactive and real-time 3D environment for customers.Through the research of algorithm about cloud modeling and dynamic simulation proposed by scholars at home and abroad,it is found that there are mainly three problems in the existing algorithm:Introducing the complex mathematical model which makes the calculation complex;Unable to realize the user-defined cloud shape;Unable to realize the simulation of meteorological elements of the cloud.This paper proposed these methods aiming at the questions above:(1)Three-dimensional modeling and visualization of the cloud based on cellular automata and particle system;(2)Meteorological three-dimensional reconstruction based on Marching Cubes algorithm;(3)Three-dimensional modeling and visualization of the cloud based on meteorological elements.Three-dimensional modeling and visualization of the cloud based on cellular automata and particle system:Combine the cellular automata with particle system to realize the three-dimensional modeling and visualization of the cloud.First,use the principle of particle system to simulate the outline of the cloud,then generate uniform particles in the bounding volumes of the cloud through random function,build the cloud particle system,and initialize the particle number,size,location and related properties.Then the principle of cellular automata system is adopted to deal with uniform particle simulated by particle system to make it conform to the rules set by the user,and calculate its continuous field density.Finally,render the final cloud particles with texture map,simulate the more realistic three-dimensional cloud.Meteorological three-dimensional reconstruction based on Marching Cubes algorithm:Linear interpolation method adopted in Marching Cubes algorithm is not applicable to meteorological data,so trisection of the boundary of voxel was proposed in this paper to solve the problem,and it has obtained the good simulation results.This improvement guarantees the rendering quality of iso-surface and not only reduces the number of triangles,but also to reduces the redundancy and increases the rendering speed.At the end of this chapter,single track was proposed to reduce the consumption of the algorithm while the hash table is taken as data buffer.Three-dimensional modeling and visualization of the cloud based on meteorological elements:One is the visualization simulation of the vector data field:simulate the wind field with streamline and improve the algorithm,render the streamline wind field with texture map.The other is the visualization simulation of scalar data field:use gradient colors to describe the data of different sizes,build the mapping relation between color and data,map different data into different colors which also means build the one-to-one mapping relation between color and data.In order to reduce the amount of calculation and improve the efficiency of rendering,the data of a certain numerical range is often mapped into a certain type of color.Finally,it realizes the method of constructing volume data through slicing data.