Dynamic modeling and rendering of grass wagging in wind

Simulation of dynamic natural scene is one of the most challenging tasks in computer graphics. In this paper, we propose a new approach to dynamic modeling and rendering of grasses wagging in wind. Through length preserving free-form deformation of the 3D skeleton lines of each grass blade and using the alpha test to implement transparent texture mapping, we successfully model grasses of different shapes with rich details. To simulate the real time waggle of grasses, the grasses of a meadow are represented in LOD, while their skeleton lines are dynamically deformed according to some physical models. Simplification technique is also employed to accelerate the collision detection between neighboring grasses. Experiments show that our method can realistically render the animated grass scenes under wind of different speeds and types in real time.