I wouldn't be doing this if I wasn't using some form of automation. I'm too lazy and uncoordinated to use GMAX as a drawing tool. It doesn't even have a proper union/carve function because it fails in math all the time.
I started modeling on a program for Quake/Hexen called WorldCraft. My room mate and I purchased a copy at like 15 bucks or something back in 1998. The program itself was great, but we ultimately had to rebuild the compilers for light and vis, because the compilers could not handle our 3D workload. Early on, I was into detail a bit too much. Kevin was more into play-ability. Together we made a good team. We need to find a way to do more team projects like that for NWN.
ok, on the topic of trees: My original goal was to create a series for pine forest, another series for spruce forest, and then pretty much fill wetter cracked rises with aspen, and then release placeable trees as: pine, spruce, aspen, cottonwood, birch, and scrub oak. This would allow me to duplicate the black hills feel. But that method would require thousands of tiles with fixed crossers. At best, if I did it as corner terrain, that is still near 1000 tiles.
on rocks: I originally wanted to supply a rockless grass terrain, a schist terrain topped with pine needles, and a bare granite terrain. I then wanted to offer placeable granite boulders, schist boulders, schist shingles, deep mine debris, and decals of various crushed rock textures to cover up the bare granite landscape. I know now that doing granite and schist separately is an ungodly quantity of tiles, and could be easily done as two separate tilesets. But I also know that just offering large walk-blocking outcrops can serve the same purpose, and lets the builder fashion at least 3 varieties of tiles by hand.
It may be best to ultimately leave the tiles as naked as possible and release a massive package of placeables. When defined as static, that allows the builder to create a low-cost environment, and allows me to move forward with other tilesets and placeable kits.
I may recarve the granite structures in such a way that it leaves much more room for the area builder to place various shapes. This should allow the builder to choose a tile modifier that could represent rounded granite, layered granite, layered schist, or some other combination. If I take a clue from the construction method of Torchlight 2, I can build a variety of limestone which can also be applied to a cliff edge, and then we'd have the full combination of anything you might see in the black hills.
Let me see if I can whittle at the count a bit and come up with an easier functioning build.