Best DXF version to export from Corel

[DieselFumes]

I see a few options to select from in terms of dxf file version when I save or export from Corel. Which one should I use?

[plasmanewbie]

There really is no single best version, I believe your best to go with the newest dxf version that your CAM software will accept and process properly. Start with the latest and work your way down until you find the best fit for your setup.

[tcaudle]

I don't think any of the versions Corel DXF export supports the more advanced arcs and polylines. Even if they did most import filters can't handle later DXF types . CorelDraw turns the arcs and curves into hundreds of tiny line segments and it makes for lots of nodes and lots of lines of code.

If the art is not already segmented and has Bezier arc and circles (native CDR or formats like PDF and VG support that) then export in SVG to SheetCAM and keep the smooth arcs and cut your node counts by factors of 10 or more. Id you CAM program does not support anything but DXF import than it might be time to look at other solutions.

Option 2 is to save the Coredraw in an older CDR format (X14 oir X4) and import directly into Inkscape . it works natively in SVG and will export directly to SheetCAM to build toolpaths that are smoother and cut better.

DXF is viewed by a lot of vendors as a |print format meaning as long as it looks okay on paper its okay. If you are buy artwork in DXF chances are it not the version with arcs so its already ragged before you start. AutoDesk never intended DXF to be a format to let you use other packages to import and easily edit the files in and its not an open file format that is documented . Its changed often and the changes are not published .

When you sop for clipart or cut files try ot get files in SVG, AI, PDF , CDR or EPS formats. I thik native DWG (Autodesk internal foramt) may support complex curves not segment them but not many drawing packages can import that format and no CAM I am aware if does.

The commercial printing and decorative art (like embroidery, t-shirt printing, silk screening, etc) figured out many years ago that true vector formats like the ones I listed were best for doing the type work they produced.. DXF came ou tof the CAD world .

[adbuch]

CorelDraw turns the arcs and curves into hundreds of tiny line segments and it makes for lots of nodes and lots of lines of code.

Perhaps this may have been true with much older versions of CorelDraw - but it has been my experience using CorelDraw 2020 that drawings exported as either svg or dxf produce g-code on par with the same drawing files processed using Inkscape. So no need to save as an older CDR version and import to Inkscape to save as svg. In fact, the CDR to Inkscape to svg can result in more lines of code than the same file exported directly from CorelDraw.

David

[adbuch]

I see a few options to select from in terms of dxf file version when I save or export from Corel. Which one should I use?

I would recommend that you export as either dxf r14 or svg 1.1 for import to SheetCam. I have found that both file types produce similar quality results.

David

[DieselFumes]

Ok makes sense, thanks for the reply guys, learned much from this and started to experiment. Looks like my setup likes the R14 version which appears to save the arcs as small line segments as Tom mentioned. I am curious if the newer versions do this also with the arcs but unable to experiment more since I can't even open them. Not a real fan of that so going to experiment with svg export and see if I get better results.

[tcaudle]

If the arcs are true clean 2 or three point curves then SVG will maintian that realtionship and when you generate code yoou get G2 and G3 moves (G-code arcs) rather than lots of line segments. SheetCAM does a pretty good job of jping close nodes to not get motion problems but doe sno fix the "lots of lines issue.

A large circle in g-code is 4 lines of code with arcs. Its hundreds with line segments. One of the problems is that the more accurate and the better your table follows the toolpath, the more a ragged toolpath effects motion. Good toolpath perforamce lets you set tracking and we usually have that at.01 mm max deviation. At that setting ragged artwork causes the machine to vibrate and shake and other things to flex and cause less than smooth cuts.
I used CorelDraw for over 15 years. Their current "rent" model is not one I cart to participate in. We used to sell a plug-in called "DXF Tool" that took a DXF and turned the stitched line segments to arcs but after Corel and others started to support SVG it became obsolete. If they (Corel) improved their DXF export that is good BUT most import filters won't be able to handle it and you will be back at R12 or R14.

[DieselFumes]

Thank you for the detailed explanation Tom, learned a lot right there. Sounds like going to svg will be the best solution for me. I have not yet had an opportunity to give it a try but will in the morning. I appreciate your time.

[adbuch]

Here is a comparison of svg vs. dxf g-code for the same circle created using CorelDraw and post processed using SheetCam. The resultant g-code is identical.

CorelDraw dxf vs. svg export for g-code.jpg (86.51 KiB) Viewed 4730 times

[adbuch]

Here is another example showing a random curved shape created using the CorelDraw B-Spline tool, then exported as both dxf r14 and svg 1.1. After posting using SheetCam, the resultant g-code files both contain about the same mix of G1, G2, and G3 commands. In this case, the g-code file from the svg actually contains more lines of code than the one from the dxf.

These are only several examples, but based on these results I believe that either file type (dxf r14 or svg 1.1) created with CorelDraw will most likely produce similar results when post processed with SheetCam and cut on a cnc plasma table. The quality of the result may depend more on the actual table/controller and the actual arc resolution setting of the controller/control software.

David

[adbuch]

I have not yet tried any of the newer dxf export options.

David

dxf options.jpg (48.67 KiB) Viewed 4727 times

[DieselFumes]

Very interesting David, maybe Sheetcam is doing all the legwork and coming up with the ideal path regardless of inputted file type.

[adbuch]

Very interesting David, maybe Sheetcam is doing all the legwork and coming up with the ideal path regardless of inputted file type.

DieselFumes - I'm not sure if this is post processor dependent, or not. I was using a simple g-code inches grbl post processor for my examples as it makes it easier to see the actual code without all the other table/controller dependent settings/comments.

David