The Simulation Of Rain And Snow In Virtual Traffic Scene

Weather phenomena like rain and snow are important components of the natural environment. During the vehicle driving process, rain and snow have a direct affect on driving safety. In old driving simulation system, weather phenomena, such as rain and snow, have been simulated in View frustum of the Traffic scene, while the visual effects of those on vehicle-windshield have been ignored. In the real traffic scene, both rain droplets and snowflakes on the vehicle-windshield have a great influence on the driver's vision and the different levels of rain or snow effects added in the simulation Windshield plane can enhance the weather phenomena simulation results of the system. Comprehensive above description, the simulation of rain and snow on the vehicle-windshield has a great significance for generating a real and immersive driving simulation environment.In the rain or snow process, the number of raindrops or snowflakes on the vehicle-windshield plane is great and the movement of particles on the windshield is very complicated which increases the difficulties in the Real-time simulation of rain and snow weather phenomena. Consequently, the thesis was researched to analyze the problem like How to construct simulation model and How to reduce computation complexity. The main work and research fruits are as follows.(1) This article analyzed the existing algorithms and the application. The basic principle and models of the particle systems was analyzed. Especially, we studied on the characteristics of rain and snow which adhered to vehicle-windshield, analyzed the key issue about rain's and snow's simulation including the shape of snowflakes and raindrops, the movement of raindrops and the vision effect of rain's and snow's scene and so on.(2) Based on particle system, a simulation algorithm has been designed which simulation the rain and snow on vehicle-windshield. Firstly, the simulation algorithm analyzed the characteristics of rain and snow in driving simulator, constructed a rain and snow particle system general framework which applied the vehicle-windshield of simulation transport vehicles. Secondly, based the same particle frame, a simulation method of raindrops and snowflakes has been created.(3) Based on graphics engine OSG(OpenSceneGraph), a simulation system has been designed and achieved which simulate rain and snow on vehicle-windshield. The rain and snow simulation algorithm has been tested which verified the correctness and the real-time property of simulation system.In this thesis, an ultimate simulation of rain and snow particle on the vehicle-windshield has been achieved. The real-time simulation result, which is immersive, satisfies the requirements of driving simulator. The proposed simulation model can achieve different intensities of rain and snow effects on vehicle-windshield by adjusting the number of system particles, which has little effect on system performance.