Real-Time Simulation Of Interactive Snow

Using computer simulated scene about some kinds of natural phenomena is becoming more and more popular in areas such as computer game, movie industry and emluator. A familiar scene in the winter times for the most us whom come from the northern hemisphere on earth. The most methods previously for snow simulation have focused on rendering realistic snow, and have been unsuitable for real-time performance. We can also see the scene simulation of snow in computer game, but these simulations just real-time snowfall, and no sonw accumulated and other simulation relate to snow, as for as we know, in other word, we never see the scene from snowfall to snow accumulated on the scene.In this thesis, we will introduce some approachs relate to simulation of snow, which includes simulate snow fell, the model of snow movement base on physics, snow accumulated and snow stability, with a goal towards achieving real-time performance in our simulative processing. The following include our main work: 1) The method of snowflake rendering base on billboard technology.2) The model of snow movement base on physics. Take into account that environment factor like wind, temperature and humidity.3) A flexible and dynamic grid model, which uses five free controllable grid cover onto the object for building up the object's figure, then offset the vertex of dynamic grid to simulate accumulation during snow.4) A method of grid mapping with fast and simple. By using this method, solving the efficiency problem that the object collide with a mount large numbers of snowflakes; how to render the snow texture at the right place when snowflake fell on the object's surface; and how to offset the grid's vertex to simulate the accumulated face.5) The model of snow accumulated and stability. Using an angle of repose to scale the stability of object's surface, estimate what the mount of snowflakes surface can receive, and according it as snow accumulated. Our contribution is present a method to simulate accumulation of snow using a kind of flexible dynamic grid model in real-time. We can create the dynamic grid on any surface wants accumulated, we use five free controllable grid cover onto the object for building up the object's figure, then offset the vertex of dynamic grid to simulate accumulation during snow. We can see the whole process that the objects'surface from without snow covered to snow accumulated; meanwhile, in the process of snow fell, we can change the wind, temperature, gravity etc, for observing the behavior of snowflake movement under different outer environment. Our method can be meet requirement of real-time snow simulation in game industry.