I have ran into a problem which I cannot seem to fix and it is poor shadow quality. I've tried changing the resolution of the shadows and its improved the quality, but still not fixed this problem.

The boulder is proving to be challenging as I try and figure out which method makes the most realistic looking boulder. Currently I used a nurbs sphere to shape it then converted it to a polygon and fine tuned it. Still not happy with it, but would like to fix this shadow problem in the meantime.