[JagWire]

The only mainstream CAD software for mac that I know of is VectorWorks. The last version I used was around version 9 though, and at least then, it wasn't much like Inventor at all. It wasn't nearly as intuitive and easy to model things as inventor; but again, I haven't used it in quite a few years, so that may have changed.

The CAD/CAM software industry is pretty well dominated by windows. If I ever found a good combination of CAD and CAM for mac, I'd buy it in a heartbeat; dump windows and never look back.

For now though, the best I can do is just run windows through bootcamp on my mac. It runs pretty well, and since I don't use my windows partition for anything other than CAD/CAM, it doesn't get viruses so it stays in pretty good shape and hasn't given me much trouble.