Hi okapi, there is a converter that I wrote that you can download from here:

http://moi3d.com/wiki/Resources#3dmCurves2DXF_converter

If you download that and unzip, you'll get a program: 3dmCurves2DXF.exe - when you run it it will let you pick a 3DM file and then it will generate a DXF file.

The curves in the 3DM file will become spline entities in the DXF file.

Does that work for what you need?

In the future at some point that will probably get built more directly into MoI, but DXF is a relatively complex format that can contain a variety of different kinds of things in it, so it will probably need a bunch of options to control it. So it will be a fair amount of work to fully support it - that's why it is not built directly in currently.

But if those programs will read spline entities from a DXF file then that converter above should get the job pretty easily right now.

- Michael

Hi Michael,
that would work just fine.
But I tried running it with some very simple files (1 rectangle for example) and the files are coming in empty...

If I open the DXF in Rhino it works fine.
If I open the DXF in modo or cinema4d, there is nothing showing.
(If I save the dxf in rhino and open it again in modo or C4d, it comes in fine).

Do you know what this could be?
thanks,

Hi okapi, I'm not really sure, but possibly those other programs will only read some certain kinds of entities out of a DXF files and not SPLINE type entities.

Maybe Rhino writes out that rectangle as a POLYLINE type entity in the DXF file and that matches up with what those programs are looking for.

I could probably figure out some more details if you could post 2 example DXF files - one with a rectangle in it that did not work going into those other programs, and one with the rectangle DXF file that does work.

- Michael

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.