How best to convert a 3D model to 2D?

What is the best way to convert a 3D Rhino file into a 2D .dxf?
When I asked an engineer at a waterjet cutting firm if he could submit a quote on cutting my parts he asked that I send him 2D drawings, specifically .dxf or .dwg files.
In the process of using Make2D on the first part, it turned a closed polysurface into 153 curves; 24 of which are closed (circles forming lightening holes). Closed curves forming rectangular holes in the closed polysurface are no longer closed.
Is that acceptable? I thought I’d ask here first rather than risk annoying a potential vendor and more egg on my face than usual. - David

Which is the best way? That depends on the project.

It’s difficult to say what the best solution is but you might get better results using the Unroll command to orient faces into XY plane…

Can you post an example?

Sure. I assume that to convert a drawing to G-code, the lines need to be contiguous. Total nube at CNC machining here.
DFCP031022Make2D.3dm (2.2 MB)

If Its waterjetting then you can probably put the part flat down explode the poly surface and with the top surface selected go DupBorder. That should give you a good result.


The only thing you need to do is run the Join command to join the the remaining open curves and then export as DXF with the Splines scheme.

The DXF attached contains 30 closed curves.

test.dxf (304.2 KB)

I don’t see Splines scheme option when choosing Export Selected>.dwg or .dxf. I’m using Rhino 5. I might have disabled it. I don’t see it in Export Options. Is that a feature added after Rhino 5?

Oh I’m sorry I actually renamed it a long time ago.

The original name of the scheme was 2007 Polylines. I changed it for waterjet cutting exports.

The important bit is to tailor the settings to your needs and check whether your laser service can work with splines or whether they might need lines and arcs or in worst case can deal only with polylines…

Thanks Martin. I think I’ve disabled the Options dialog. I’ve looked but so far have not found how to turn it back on.

The _ResetMessageBoxes command should fix your problem.

Rhinoceros Help - ResetMessageBoxes | Rhino 3-D modeling (

To be entered in the Command line I assume. Here’s what I get:
Command: ResetMessageBoxes
Unknown command: ResetMessageBoxes

Seems to be a new command which wasn’t available in Rhino 5.

Check this thread:

How do I reset import options / restore import pop-up box - Rhino / Rhino for Windows - McNeel Forum

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Thanks. Will 2004 Polylines suffice? I’ve got the latest update to Rhino 5.

AutoCAD Export Schemes

Yes but once you accept 2004 Polylines, you might want to change how your curves are exported.

Got it. I’ve emailed the vendor to ask what he needs. I very, very much appreciate your help, Martin. It’s the help I’ve gotten here and from tech support since purchasing Rhino 5 that braces my belief that Rhino and this community is beyond awesome. - David

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Thanks :slight_smile:

Hi David -

That’s basically the only that that works :+1:
There are so many different systems with different requirements…

Hi Wim - thanks. - David