Autodesk Inventor is known for its open approach to foreign file formats. It includes translators for import and export of many popular file formats used in the mechanical industry – you don’t to buy any additional software to read and write STEP, IGES, Parasolid, Catia files, etc. Importing foreign 3D models is a rather common and frequent job – at least I do it almost daily.
Mark Flayler from Imaginit has published a clearly organized table of all translators available in the current versions of Inventor, including Inventor 2011. Download this PDF file from his blog.