Dxf export, What to think and what to do?!

I know this is a question that never will have a definite answer but I am having some trouble with this issue again…
I am exporting curves to a laser-cutter (industrial) in .dxf format. When viewing them in AutoCAD they look like sh-t (see attached images) but when importing them back into rhino the look good. So what will my laser-cutter guy see?? Crap or files he can use? Havent sent them to him because he´s a very stressed man…

test1.dxf (949.1 KB)

Did you do a regen after importing them into ACAD? I think if you are re-importing them into Rhino after export and that they look OK, then the export is geometrically OK.

That being said ACAD classically handles splines pretty poorly, and the quality of the import will also depend on what software your laser guy is using to run his machine. Since what you are exporting appear to be splines for the most part, you will maybe need to convert them to lines and arcs before exporting. You might also just want to see what the importing program does with objects that have been completely exploded and simplified.


Hi Mitch!
I assume he is using Bysoft7 for his laser http://www.bystronic.com/en/Products/software/BySoft-7.php , but with that I dont know how it will treat dxf formats.
But what does it mean with completely exploded and simplified? I dont want him to get a million or more small segments of curves that is wrong in some way.
And no I did not try to regenerate the curves in Acad…Will try that tomorrow.
I also have some files that consists of both circles (holes and perimeter) and segmented curves (see attached) and I dont know how to export them on the same export…


Well, it depends. Some laser cutters I have dealt with in the past wanted everything exploded into separate entities - i.e. 4 lines instead of a rectangle. But that you need to check with them. Most of the time I try to keep polylines at least joined.

With the right export settings, your circles can stay circles, polylines can stay polylines etc. The main problem is splines (if you have them) and what you choose to do with them. Some systems can read splines correctly, others can’t. For those that can’t, you will have to segment them into polylines, how fine/heavy those are will depend on the tolerance you need to hold.

One thing that should perhaps be avoided is joining spline entities to line/arc entities. Rhino can do this, but AutoCAD and many other programs can’t, and don’t like to import them either - so it could result in a distortion of those curves on the import end.

I know you don’t want to bother your laser guy, but you are likely going to have to try a few tests together to find out what export settings work best for him.


Hi Mitch
And thanks for info. Regen didnt do anything to the curves in Acad…Still looks like crap, (I dont like Acad!)
Ok will have to bite the bullet and try to talk to the stressed man him self…
Best regards

Could you post a portion of the Rhino file and the corresponding portion of the exported dxf? I’d like to see what is going on in ACAD… (or maybe send it to me via PM if it’s not for public?)


Hi Mitch
PM sent to you!

You’ll need to take the time to convert your Rhino degree 3 and higher curves to arcs before exporting, or only draw, lines, arcs, and circles in Rhino that AutoCAD supports.

Rhino is NURBS based.
AutoCAD has no provision for NURBS, so you need to convert the unsupported curves in a more intelligent and useful way.

This will be better than converting Rhino Polylines into AutoCAD Splines.

Use the Convert command.
Tolerance=[your waterjet cutting tolerance]

Set the other controls to your choice.

Can you post or send me a portion of your 3DM file too?
I’ll do the arc conversion process and send you a 3DM file that is ready for export to DXF.

Hi John
And thanks for the info but all went well with my laser cutter guy, I made some changes in the export setting and Mitch had a look at it also. I cant say that I have become much wiser… But next time I maybe send laser files in another format. He could read step iges or solidworks files also.
I will send you a pm with the files I sent to Mitch (not for the public yet…)
Best regards

Sure it does. I don’t know exactly how ACAD treats this stuff internally, but below is a file with a polyline and degree 2, 3 and 5 splines. The originals, drawn in Rhino, are on the cyan layer. I then saved the file as a DWG, opened it in ACAD 2015, and re-saved it out of ACAD under a different name. Then I re-imported the new DWG in Rhino.

Note that when you SelDup, the 3 splines select. Funny, the polyline doesn’t… Don’t ask me why on that one.

What you do need to be careful is messing around with polycurves with different degree elements, sometimes that can cause trouble. However, we run stuff made in Rhino, ACAD, VectorWorks, and ArchiCAD all to our laser via DXF and either Rhino or Type3 every day. We have the most communication problems between VectorWorks and Type3, rarely any problems between ACAD and Rhino.


Splines-ACAD.3dm (43.3 KB)

AutoCAD supports splines.
Rhino can make splines but is not limited to them.
AutoCAD splines are not a universally supported object. It depends on the tool path generating tool.

If IGES is an option for @perolalars, that would probably be the most robust and easy to use as very little changes with the file translation.

Thank you so much both of you for help when needed! I will try to stay out of dxf format from now on and ask if the manufacturers cant use another file format. It is possible to use it but as Mitch does it, ones have to have some basic understanding of the two different universes Rhino and Acad inhabits…
Cheers guys and I owe you both a beer…

I think I recall exporting mastercam surface files for cnc 5 axis milling with good success. The cutter had to do a little final processing to close up all gaps. I see now that that option no longer exists. Am I dreaming?


Mastercam is still on the IGES export “flavor” list

Thanks, John B.

PERLOLARS, you might wish to give Mastecam a go.

We had good results cnc routing boat hull and deck patterns.



Hi Tommy
And thanks for tip but I use RhinoCAM for my own built cnc router. And the iges export from Rhino works good for me for now.
And it was for a laser cutter this time.

Okay P.,

Good luck with your project.

Keep us posted on what you find is the best way forward.