Inventor Fusion is a 3D modeling software that uses direct manipulation. It unites direct modeling and parametric workflows. The best part is that it is free! It comes standard with AutoCAD 2012 (for Windows) and is also available as a free download in Autodesk Labs. Fusion is created to work along with AutoCAD, Inventor (of course), Algor, Moldflow, and Design Alias. As an example, while working on a 3D model in AutoCAD, click the Export to Fusion button and it is. Edit the model then put it back into AutoCAD. They work together. Fusion can also be used as a standalone program. You don’t need anything else.
The new Mac version of Inventor Fusion will be available in the first quarter of 2012, which is just around the corner so it won’t be long.