URGENT issue with a CNC laser prototype

Goodmorning everyone!

I have an urgent problem to solve :

I worked a vector file with Illustrator and then I exported DWG / DXF to enable printing on laser CNC ( I left: “Maximum editability” like options ) .

But I found a problem : the technicians informed me that the object appears divided in a lot of small segments and lines ( “Lines & Arch” ) … and that’s not good for the machine , which would print line by line with serious " approximation " of the final product .

I tried to open the file in Rhinoceros and , in fact , there are many small segments …
Is there a way to make these little lines become one unique line to print with CNC ? ( if I understand it , the polyline does not fit ) .
How can I simplify these lines and arcs without changing the shape of the final ? ( or leave the line curves as elaborate and not simplified and rough ? )

Thank you all for your support !

If I understand correctly all lines are connected but are all split.

In rhino you can try to select all lines and then use the command Join.
All possible lines and arcs will be joined together as 1 line.


Thank you so much!
Yes, the lines are connected each other…but all split!

The command JOIN is, simply, the one with “puzzle pieces”?
Because I tried…and on the information about the line appears “CURVE”…is that ok?

When I joined the lines, the object becomes as the original: only one curve…and the technicians told me that is not suitable for the CNC.
They asked me if is possible to make “Lines & Arch”, but less than now (now there’re too many little lines…they want less)

So they did all join?

But now you want to split them again at some range?

Yes, they are all join…
I don’t know why…I’m thinking that only 1 line (joint) is ok…
But the technician told me that isn’t ok and is more suitable to have split lines, but not too much short and little (now I have maybe more about 2000 lines)…so I think I have to split them at some range, yes.

If you use the command Divide and Split=Yes then you can say a length where to split.

i believe they’re asking you to give them the .DWG in lines&arc scheme.

this setting is available when exporting the file.

File-> Export
choose AutoCad drawing(dwg)
click the Export button
in the drop down menu, choose R12 Lines & Arcs
click Export

Thank you Jeff.
Yes, I did it. but they told me that there are too many lines and they need less.

hmm… sorry then as i’m not sure what the problem is.

fwiw, this past month i’ve sent 5 models to cnc or laser using .dwg export in Rhino for Mac and all has worked fine.

can you upload your .3dm here so people can look at it?

[edit, actually, the guy with the 5x12 table took .3dm files… but two to laser and another to a punch press via .dwg and they went smooth… “files were fine” etc.]

Are there only lines and arcs in the file or are there splines? Splines will be converted into lots of tiny line segments. You might try joining everything in the file then exporting as 2004 Natural which will preserve polylines, arcs and lines. Otherwise you may need to create a custom export template.


Unfortunately I don’t have the permission to upload the file…
Maybe I can upload a similar one…UPLOAD.dwg (1.4 MB)

In the example that you sent there are only straight lines. The SelLine command selects all (when you explode the inner polycurves) [Note, those inner curves are doubled up but not identical].
If I understand the problem, it sounds like the manufacturer is expecting smooth curves - try to join all lines that look like they describe a single arc (-ish). Then run Rebuild on this joined curve and change to point count to a number that results in the deviation that you can live with. On the outer chain curve in the example, I’ve joined a section and rebuild with 11 points (118 originally) which results in a deviation of 0.000986841 units.

I’m not sure to understand.

Yes, they expect smooth curves (and on Illustrator I have it! )

I noticed that: when I save in DWG file, my smooth curves become straight!

It depends how you export them…you can modify the export profile to match your needs. The problem is that some kind of geometry is not supported by some CNC control software…

Illustrator can export splines and polylines in DXF/DWG. It does not export Arcs.

If your CNC service requires arcs instead of splines/beziers, you will need to import your illustrator file into an application that can create arcs from spline/bezier curves, or get a plugin for illustrator that can export arcs like EX-DXF Pro from BabyUniverse.

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Rhino can do that. Use the “Convert” command and set the “arcs” option on the command line. See the Help for other parameters.


I tried to convert the lines into arch…but remains always little segments

Thank you all for helping me.

I leave another file…
This one is not ok, for the CNC.
Is possible that “CONVERT Curve to Arch” doesn’t work?
'cause I select all the lines and do “CONVERT Curve to Arch”…I can show the “Preview”, but, after click OK/SEND…nothing happens.PROVA1.dwg (1.0 MB)

You need to use the Illustrator file, not the exported DWG. Import the Illustrator file into Rhino (you may have to save your Illustrator file as an earlier version, like v8 or v3) and follow Mitch’s info about using the “Convert” command

I can’t open the illustrator file (is .ai) …I’ve need to convert into DWG or DXF …
I’ll post the files “step-by-step” for show you the steps I did:

Step 1 - Open the DWG file exported from illustrator

STEP 2 - Explode the surface (for delete the surface)

STEP 3 - Here is After explosion and delete the surface

STEP 4 - Convert Curves in Arcs

STEP 5 - Appear the Preview of Arcs
(after that, in “info” appear: polycurve closed with 293 segments of curve")

STEP 6 - Details of the “info” on the left

STEP 7 - This is how apper after “Done button” for the conversion

after that…I save like “DWG” in “2004 Natural” …but, if I save it in “2004 Lines & Arcs” the problem is always the same: a lot of lines connected but split.

They send me a file for show me how they need the file:example.dwg (1.5 MB)

I was able to do arcs now! Instead of curves !
But still too much arcs (I’ve need less)