Author Topic: DXF conversion losing geometry  (Read 772 times)

December 10, 2018, 05:23:53 AM
Read 772 times

JackFabLabCov

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Hi all.

I have a recurring problem.  We get art work created in all sorts of formats which we need to convert to a DXF file for our laser cutter. 

Here is an example which was brought to us as a .AI illustrator file and saved as an SVG from Illustrator.  This opens in Inkscape fine.  But if I Save As DFX then open the file in Inkscape (or our laser's software) parts of it are missing, or changed (notice missing letters and the Apple logo turned cyan in the second image).

A colleague can put the same file through Rhino and it exports a clean DXF which looks identical to the SVG, but as a FabLab we try to use open-source or

Image 1 is the SVG open in Inkscape.  Image 2 is the DFX opened.  4-12-18 is the original file.

I've used Inkscape 0.92.1 and 0.92.3 in Windows 7 and Windows 10.

Any clues, ideas or solutions?

Jack
  • 0.92.3
  • Windows 10 and Windows 7

December 10, 2018, 06:43:31 AM
Reply #1

brynn

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Welcome to the forum!

When I compared the SVG file to the PNG image with missing text, I see that the missing letters (after ungrouping) are identified as "Object Polygon".  I don't know exactly what that means.  But the letters which still show up are paths.  So the fix for the text is probably as simple as selecting everything and to Object menu > Object to Path.

I'm not sure about the apples, why they turned green.  But can't you just change them back to black?

There are (lately anyway) 2 versions of DXF, and Inkscape prefers on of them to the other.  It may be that using Rhino produces the current version of DXF, while who knows where the files are coming from, which you acquire.
  • Inkscape version 0.92.3
  • Windows 7 Pro, 64-bit
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December 12, 2018, 07:17:27 AM
Reply #2

JackFabLabCov

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Thanks Brynn.

In the XML editor the letters that survive the conversion have id: SPLINE, and the ones that don't are id: LWPOLYLINE.  I don't know how to change from one to the other.  Object to path doesn't seem to do the job.

You are quite right about changing the colour - I am just trying to understand what is happening.

Jack

  • 0.92.3
  • Windows 10 and Windows 7

December 14, 2018, 01:50:44 AM
Reply #3

brynn

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I'm looking at the SVG before it's converted to DXF.  The missing letters are identified (both in status bar and XML Editor) as polygons.

In the DXF dialog (which maybe you just clicked through?) there are a few options.  One is Use RoboMaster type of Spline output. And another is Use LWPOLYLINE type of output.  It sounds like you maybe had both of them enabled, and the paths turned into Splines and the polygons turned into Polylines.  I'm just guessing about that, I haven't actually tried it yet.

Ok, my first test will be with neither option enabled.  Let's see what happens....  Aah, well all the text survives, at least in Inkscape.  Note that I ungrouped everything first, before I saved as DXF.  I'm not sure if that would matter or not.  I only did that to make it easier to ID the objects (not because I thought it might help).  Also, I did Not use Object to Path, although that probably would work as well.

There's some additional info on the Help tab of the DXF dialog, which might help you understand better.

The changing color may well be a bug.  You're welcome  to look into it, if you like.  If  it's not already reported, you can do it.  Start here:  https://inkscape.org/contribute/report-bugs/

But I don't think the missing paths is a bug, because it can be fixed just by using different options (or probably also with Object to Path).  Although who knows, after playing around with all these various options, you might find a way to fix the color changing.

Just re-reading your original message.  There might be a dialog for opening AI files in Inkscape (I don't have any for testing).  And if there is, it might have some options that would affect this problem.
  • Inkscape version 0.92.3
  • Windows 7 Pro, 64-bit
Inkscape Tutorials (and manuals)                      Inkscape Community Gallery                        Inkscape for Cutting Design                     



"Be ashamed to die until you have won some victory for humanity" - Horace Mann