I use a 3d program called Maya to build, animate, and render images in, then I take all the rendered images and convert them to GIF format using photoshop but you can use almost anything else to do that.
Cool, thanks. I've messed around with SketchUp and some 3d pointcloud software before. I'll check out Maya, but I'm guessing it's out of my price range (AutoDesk). Do you mind if I edit and use a couple of your gifs?