Hi Andrew,

re:
> However, If I can successfully convert this closed curve into a region and extrude it in a separate CAD
> program (and I can) then the drawing is 'clean', otherwise, it would not be possible to create a region.

Not necessarily - there are a lot of variables. It could be that the separate CAD program uses a looser tolerance than MoI for forcing things closed, or if it is some problem with self intersection it can by luck sometimes appear to be ok.

Since you can't post the .3dm model file I would recommend to instead post the .dxf file that you are trying to import. That would also allow me to do a detailed analysis of your geometry and see what's going on. Or if it is a bug in MoI's import handling I would also need to repeat the problem over here to have any chance at fixing the bug.

With just a written description or a screenshot it's not really possible to give you any more information than I already have.

- Michael