The MakeGrass macro (mgrass.zip) generates a square patch of grass of a given size and density. Each blade is independently created with its own length and curvature. The patches can then be assembled into a prairie.
The patch mesh can be saved as an include file for later use.
L'usine à Gaz-on (the Grass Factory) is a Java application inspired by MakeGrass, that exports mesh2 files and is able to cover height fields adaptively.