DXF export issues


I am having trouble exporting to DXF from 3DM, no matter which DXF option I use, the curves are exporting in 1000’s of small segments, which my fabricator/laser cutter can’t use.

I have done a lot of this in the past without these problems, just last August. Any insights?

Exporting files as dwg or dxf?
Rhino output to Epilog Fusion laser

In my company we do as follows:

  • Use the Convert command to make sure everything is lines and arcs
  • Export into DXF R12 Lines & Arcs

It should work in 99.9% of the cases, and we import/export DXF files in and out of quite a few different programs

(John Brock) #3


Your CNC mill/cutter/router follows G-code commands. G-code supports three movements:
1 - Straight lines
2 - Clockwise arcs
3 - Anticlockwise arc
It’s your job to make sure you’re only send supported curves to the water jet.

Lines, arcs and circles in Rhino are good to go.
Twisty Rhino NURBS curves need to be converted to arc chains. If you don’t convert them, they will be approximated by hundreds of short straight lines.

Since you need more efficient Arc objects in your DXF/DWG file, you’ll need to convert your wiggly Rhino curves to arc segments before exporting.

Use the Rhino Convert command.
Use these command option settings:
Tolerance=0.01mm or 0.002"

The tolerance controls how far the arcs will pull away from your NURBS curves. Your machining process and project will determine how much is OK. The distance is in current model units.


Thanks for the feedback, no matter which Autocad scheme I use, I get the
following, the curves are broken up into small segments

Last year I could export into a dxf and the curves were continuous

(John Brock) #5

Please read the previous messages.

You MUST convert degree 3 and higher NURBS curves to arc chains.

The fundamental problem is AutoCAD DWG/DXF does not support NURBS curves so they must be converted into geometry that AutoCAD can understand, before exporting.



Thanks for your help, with my fabricator I think we figured it out,
converting to arcs worked



Thanks for your reply

(John Brock) #8

One other option that may be easier, is find out of your fabricator can accept IGES files.
If so, then his CAM software should do the arc conversion automatically, and within the tolerances of the cutting machine.
It will be easier for both of you if he can accept IGES files.



Thanks for the suggestion, I’ll ask him