I use Carrara 7 Pro, a powerfull but not terribly expensive 3D modeling and animation package. It started out as RayDream Designer years ago and I've been upgrading ever since (although the upgrade to ver. 8 seems a bit pricey, that's holding me back). It's not a solid modeler like AutoCAD or SolidWorks, it's a vertex-based mesh modeler, I may not be the best person to explain the difference.
This type of 3D modeling (as I do it) is too complex and inefficient for simulators, it could be animated but the render times for a complete engine would be staggering. I've used it to have some Sn3 domes 3D printed in a plastic material by an outfit called ShapeWays. Strength and level of detail are dependent on the material you chose. I don't know if you could use for more precise work with CNC, not that familiar.
Mike McKenzie
Frankfort IL