Tool path fails on radius corners

[Howard Weymouth]

I design using Autocad 2010 and am just learning DXF2GCODE.  If I create a rectangle, I can open the dxf file and the tool path shape is a perfect rectangle.  However, if I put a radius on the corners, the tool path shape is a sort of ellipse.  Changing the tool diameter does not make any difference.  Changing the radius does not make any difference either.  I tried changing the fillet radius all the way down to 1mm and the tool path was still a big blob.  Yet it handles true rectangles without issue.  I tried replacing the radius corners with 90 degree arc segments and joining them pedit and still no luck.  I'm probably missing something very basic.  Can anyone point me in the right direction?

[Christian Kohlöffel]

Can you attach the dxf, which produces the problem and a picture how it looks like what you get as an output.

 

Regards

Christian

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[Howard Weymouth]

I figured it out!  I had been saving my DXF files in Autocad 2000 format and was assuming that 20 years was old enough to ensure compatibility with any software used to process a DXF file.  As a last resort, I switched to Autocad R12 which is the oldest format my Autocad 2010 can save.  That was it!  I then tried Autocad2010 DXF format just in case Autocad DFX 2000 was a bad version but it too would not open properly.  Only ACAD R12 DXF format works for me.  Lastly, I tried multiple file formats,  ACAD 2000, ACAD 2010 and ACAD R12 on a different computer running Windows 10 with the same results, only the R12 DXF format works processing a corner with a radius.  I have attached screen shots showing the tool paths.    Thanks for the offer of assistance Christian.

[Adam Geary]

I've been using dxf2gcode for several years now and have always used the 2007 DXF format just fine until I updated to the latest version just now.  Thanks for pointing this out as using version R12 has definitely solved it.  

This may be a new thing with one of the later versions.  Upon examining the Gcode, I noted that it was flipping the direction of the I and J values as well as swapping I with J sometimes within the G2 and G3 commands.

The version I had been using for so long was:

Py3.4.4 PyQt5.4.1: $Revision: 306a57208bc233b86be368bd019159e3d0d9afcf $

Last change: $Date: Sun Apr 17 16:32:22 2016 +0200 $

[Christian Kohlöffel]

Hi Adam,

 

can you forward me a simple example file with instructions how to create the bug. I didn’t find the issue up to now. This would help a lot in order to solve the topic.

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[Adam Geary]

Certainly, but I don't seem to have permission to post attachments or to reply to you directly, so I'll have to improvise with a link.  

Upon testing just now, the R12 version DXF has also exhibited bugs in the exported .nc file, so I think this is a separate (more serious) problem from that which is seen in the display.  Going back to the older dxf2gcode version seems to solve this. 

Here is a link to a zip containing the 2007 version DXF I mentioned, the dxf2gcode project file of that DXF, and the output gcode .nc file, followed by the same three files but starting with an R12 version DXF.  And since the problem is not completely solved with R12 DXFs, I will also include the project file and .nc output from an older 2016 version of dxf2gcode which doesn't have this problem.

When opening the 2007 version DXF with the dxf2gcode version from the DXF2GCODE-2019.10.25-win32.msi installer, I see the following.  Note that the scrap layer has wonky curves, but the circular shapes look correct.

In the 2007DXF version .nc output file, visualized below, lines 119 and 135 have the I and J values inverted, despite displaying properly in the dxf2gcode window seen above.  

Which G2 and G3 commands exhibit this error seems to vary.  I've tried this several times and it has been different each time for some reason.  Possibly something in the optimize shapes option?  Sometimes it swaps I with J instead of inverting.  It has now also produced a similar result using the R12 DXF version.  In the failed R12 version, note that lines 103, 119, and 135 are all incorrect.