help with 3D.

For what you want to do, I think the bushes or the stone walls would work best, but I would be curious to see how it looks done with fence. The bushes tend to give it more of a step down into the hole where the fences tend to give the illusion of flat walls. So it really depends on what you are after.

I just bought the skyscraper and magnifying glass, so now I am done with big purchases and get to bring in the bulldozers and flatten my house farm. Which is where I plan on moving the UFO bunker to and making my own little area51 in Springfield.
http://i.imgur.com/dvXcqhP.jpg