In January, it was noted that Autodesk was planning to bring its Inventor Fusion mechanical design software to the Mac. At that time, the company promised that the a free technology preview of Inventor Fusion for Mac would be available in the coming weeks, followed by an official release later.
On Tuesday, 17 April 2012, Autodesk announced that the free software preview is now available for download and will remain active through 1 January 2013.
Inventor Fusion is a free technology preview that enables creation of designs through intuitive direct manipulation tools. Our aim is to set a new standard for Assembly design, giving users greater control over designs without sacrificing productivity. Hopefully this technology preview will make it easier to open and edit 3D models from virtually any source and incorporate them into new or existing designs (such as in Autodesk Inventor). Your feedback will determine if we are correct in our thinking.
The system requirements for Inventor Fusion for Mac include most relatively recent Mac Pro, iMac, and MacBook Pro models with specific graphics options from AMD, NVIDIA or Intel. However, Autodesk has indicated that users may still have success in running the software on officially unsupported systems.
Source: Mac Rumors