Topography
Definitely get Quicksurf from Schreiber Instruments. You could
probably get more info about it in the ACAD forum (GO ACAD), but it's
an excellent surfacing tool that works inside of AutoCad. A friend
and I did an animation that included topography by Quicksurf, and we
had to tone down the detail level just to get it manageable in 3DS.
Too many polygons to start with. I think it started out as + or – 5
feet, and ended up as + or – 50 feet, still extremely detailed
considering it was a mountainous region.