Actually, you can only barely call it CAD, but Google (the do-no-evil empire) has a new free 3D drawing program. Check out SketchUp. I think Google is playing a really long con loss-leader marketing game with us. They’re going to make us all so addicted to their little internet-changing products that we won’t even remember the world without them, and then, WHAM!!!, pay up, user scum. Mark my words.