David Edward Gaskill sent us a trick for converting Autodesk Inventor files to AutoCAD DWGs.
"I have had issues with the conversion from Inventor to AutoCAD; the process converts some of the views, but not all. A better method is to use SaveAs to save the file as a DXF file, then dxfin the file into AutoCAD and save the file as a DWG. This will convert all the views to single line editable objects. It works nicely — this method will even convert the shaded views to a single line drawing. Hope it helps."
Notes from Cadalyst Tip Reviewer Brian Benton: Although Inventor and AutoCAD create and use different types of files, they can work together. Inventor creates a model file from parts and assemblies. I could not save this type of file to a DXF format, although they could be saved into DWG, DWF, DWFx, and many other formats. But sheet files in Inventor (drawing files) can be saved as DXF files, and can be opened by AutoCAD (as described in this tip).
Another thing to try is Inventor Fusion — a lighter version of Inventor. It's a free program that comes with AutoCAD 2012. It can open DWG files and Inventor files; it also works well with AutoCAD. It's meant to work in conjunction with AutoCAD to help in the 3D modeling process. Changing files from AutoCAD to Fusion works well.