Ronen Bekerman has a great tutorial on using Instanced geometry and proxies to create “ground covering” in the form of rocks, grass, and leaves.  The results are amazing and go a great ways to add realism to a scene.  He uses several scripts to make it easier, and provides links and details on each.

Advanced Painter script (found here at the script spot) was used to paint / scatter on the ground surface. I loaded the objects I wanted to paint on the ground into the list, selected the ground as the surface to be painted on – and started to paint away!

You can adjust your settings according to your needs as you go along. The Advanced Painter script is really powerful… It has become a regular part of my workflow.

via 3D Ground Cover Modeling in 3D Studio Max – Ronen Bekerman – 3D Architectural Visualization Blog.