Biological Weathering Simulation Based On 3D Cellular Automata

As a common phenomenon in outdoor scenes,weathering simulation is widely used in games and virtual reality.Weathering is geologically defined as the disintegration or alteration of rocks in situ due to physical,chemical,and biological factors.Biological weathering is the weathering caused by biological factors,manifested as the growth of animals,plants or microorganisms on rocks,covering the rock surface and producing corrosive chemicals during metabolism,causing corrosion and appearance changes.A direct way to simulate it is manually modifying the models and materials.However,this operation is tedious and repetitive,influencing the development efficiency.In computer graphics,there have been a variety of studies to achieve the effects,usually based on the macro or micro laws of weathering,with mathematical and physical models.But so far,the simulation objects are mainly focused on physical and chemical weathering,and there is less research on biological weathering simulation,and it is mainly based on offline rendering.The complex calculation is difficult to apply to real-time conditions,such as games and virtual reality.To solve the problems,this paper mainly focuses on biological weathering,designing a 3D CA-based method to simulate the growth process of moss and lichen on rocks under real-time conditions.The research mainly includes: preprocessing the rock model using a parallel GPU-based voxelization algorithm to obtain the cell space;designing cellular automaton models in 3D space to simulate the weathering process,including the 3D-Moore-neighbor-based CA and Improved Diffusion Limited Aggregation Model.Meanwhile,to realize the effect of environmental factors on the weathering process more closely in real weathering,a fitted environmental impact function was used to construct the influence of environmental factors(such as humidity,temperature,and light)on the growth rate of organisms.To obtain realistic weathering material,a PBR technology is used to optimize the BRDF in the rendering equation for the characteristics of rock and biological materials.The method designed in this article is integrated into the current mainstream game engines,based on real-time rendering,and seeks a balance between visual effects and efficiency.