Grass plays an important role in most natural environments. Most
interactive applications use image-based techniques to approximate
fields of grass due to the high geometrical complexity, leading to visual artifacts. In this paper, we propose a grass-rendering technique
that is capable of drawing each blade of grass as geometrical object in real time. Accurate culling methods together with an adaptable rendering pipeline ensure that only the blades of grass that are
important for the visual appearance of the field of grass are rendered. In addition, we introduce a physical model that is evaluated
for each blade of grass. This enables that a blade of grass can react
to its environment by calculating the influence of gravity, wind and
collisions. A major advantage of our approach is that it can render fields of grass of arbitrary shape and spatial alignment. Thus,
in contrast to previous work, the blades of grass can be placed on
any 3D model, which is not required to be a flat surface or a height
map.