Can someone verify if this is the same in 2017?
When i open a file i have the option for filetype .stp, but when i start a new part and click "import" to make a multisolid from the same file it doesn't list .stp as an option.
(if i select "all files' it does show them and import works)
This has been corrected in 2017 but as you can see in this article (at the end), it describes your workflow.. 
Mark Lancaster
& Autodesk Services MarketPlace Provider
Autodesk Inventor Certified Professional & not an Autodesk Employee
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