Hi Lewis, so the reason why the current file name is only set when reading a 3DM file is that is the "native" format for MoI - it is the only format that MoI can store everything it can create into.

If you open a STEP file the current name isn't set so that if you do a plain "Save" it will open up a dialog for you to explicitly choose a format rather than just automatically saving back to a STEP file which will then lose views and background bitmaps that you may have created for example.

This is mostly a concern for a plain "Save" that doesn't show any dialog though. I'll have to think of it for a bit but it might be ok to do what you describe only for "SaveAs" or "Export" and not for "Save"...

- Michael