Bump mapping is a computer graphics technique where at each pixel, a perturbation to the surface normal of the object being rendered is looked up in a texture map and applied before the illumination calculation is done (see, for instance, Phong shading). The result is a richer, more detailed surface representation that more closely resembles the details inherent in the natural world.
In other words, it makes the ground look "bumpy".
Einstein has spoke....
http://en.wikipedia.org/wiki/Bump_mapping
It may. I only lose 2 fps though with it on and it makes the terrain much more realistic looking.
Thanks, Lusche. So turning it off might speed things up for the folks who are on the thin edge of playability?- oldman