Abstract: Grass, lawn, and meadow are common features of outdoor scenes. However, animating the grass motion under the influence of wind could be a daunting task especially if the subtle variations between grass blades are considered. Collectively, those variations of individual grass blades may produce interesting phenomena, such as the eye catching wave-like motion of a meadow. In this work, we develop a framework that simulates the grass dynamics under a plausible wind field. We first test it with a small bunch of grass blades (Figure 1) and validate it with the motion of real-world grass. By utilizing the tessellation shaders and geometry shaders of modern GPUs, we make our grass model as efficient as possible so that it scales well to a large meadow, which is also exposed to a plausible wind field simulation. As a result, our grass simulation runs in real time for meadow scenes consisting of hundreds of thousands of grass blades, and produces convincing wave-like motions when the wind blows over the meadow.