Do most CAD programs work on a Mac?

I would take a look at BricsCad which is native to both Mac and windows. It is supposed to be very similar to Atuocad and is way less expensive. It uses the Autocad file format. Also check out IMSI software, I think there is a Cad for Mac there to. Another Mac softwre is Vectorworks but I'm not sure it is for engineering specifically. It is for 3D "BIM" modeling. I'm pretty sure all these are Mac native so they will not be slowed down by trying to run inside something else on your Mac.