Hi Michael,
here are three files.
This is a very simple setup.
The lines are imported into both modo and cinema4d when the 3dm file is exported via Rhino.

Hi okapi, thanks for posting the files.

It is like I had guessed - the one that works has the object stored as a POLYLINE entity, and the one that does not work (from the conversion utility) has it stored as a SPLINE entity.

So it looks like Modo and C4D only support reading Polyline data (which are a sequence of line segments) from DXF files and not actual smooth curves.

Right now there is not any way set up for MoI to write that particular kind of data to a DXF file, so you will need to use Rhino currently to do that conversion.

- Michael

Thanks for looking into Michael.