Autodesk has released a new software for do-it-yourself users and makers, "123D" (one-two-three-dee). It is a great tool to design 3D models and have them physically manufactured in many interesting ways. Not only through 3D printing.
123D is based on Autodesk Inventor Fusion and uses a similar user interface. Its native file format .123d is in fact just a 3D DWG format. One of the important functionality of 123D is its rather broad support of 3D CAD formats. With the help of this feature you can use 123D as a free CAD converter.
Autodesk 123D can read (import) files in the following formats: .123D, .DWG (3D), .STEP/.STP, .OBJ, .SKP (SketchUp), .123C. The imported 3D model can be then exported (written, converted) to one of the following formats: .SAT, .STL, .STEP/.STP, .DWG, .123D. These CAD conversions work quite reliably with an exception of .SKP - many .skp files I have tried failed with an abort of the 123D application. But 123D is still in beta so we can expect improvement in this area. So if you need a standalone converter of common CAD formats, you can use Autodesk 123D.
Download your free copy of Autodesk 123D at www.123dapp.com