Google has a free 3D drafting program called SketchUp. I think they started it so people would make 3D images of buildings and then place them on Google Earth. It allows you to draw buildings and other objects to scale or in real dimensions. Check it.
It’s easy, too. I made some mildly impressive renderings of one of Leo’s shelves and a machine that could make it the very first time I tried it. Ask, and I’ll send them to you.
i played with it. pretty nice…quite powerful.