Cut shape completely wonky from shape in PDF file

Just ran this test job trying to cut a few different hole sizes. PDF file looks fine when I view it, and shapes looks fine in the GF UI. I rotated and arranged stuff to run on a bit of scrap material (medium maple). When I ran the job, all the engraving was fine, but two of the three circular parts of the my test holes were completely wonky. Any ideas why this would happen? PDF was exported from an Onshape drawing.

SNAG-0019
holeSizeTest.pdf (302.7 KB)

That looks like a pretty small scrap…did it shift when the air assist hit it? It can blow small lightweight objects around sometimes.

Sides on that scrap are about 3 inches long. I didn’t see it move.

Just tried it again. Wedged the material with some magnets and watched it closely and didn’t see any movement. Same sort of issue.

And tried it a third time, this time only rotating one of the three cuts, and rotation it to one of the 45 deg snap angles instead of some random angle. That didn’t seem to cause any problem.

I also opened the PDF in Affinity Designer and the circular parts have a zillion points! (Well grrrr, separate issue… that’s annoying if Onshape is exporting shapes so inefficiently.) So now I’m guessing that when I rotated these parts a bit at a random angle that’s caused the problem with GF processing it due to the ton of points on the curve?

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Carefully remove the head from the carriage plate and inspect the wheels that ride on the front edge of the gantry for cracks.

Yeah, the file isn’t helping. 58,000 nodes to describe three keyhole shapes. The text is equally a mess as well.

An SVG editor draws each of those keyholes with 7 nodes.

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If it didn’t shift, it might very well have been something with the number of nodes…can you simplify it with your design software to reduce the node count?

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One more test for myself to show that a random rotation angle seems to causes a problem, but a rotation at one of the 45 deg snap angles still works fine. 90 and 180 deg here is fine. Two random angles come out wonky.

Seems like the GF remote processing is having trouble with the random rotation angles, I’m sure because of the stupidly large number of points. I don’t blame GF for this because I fully recognize it’s a ridiculous number of points for such a simple curve! (My brain does wonder however, what if if actually was some sort of complicated shape with a ton of points? What’s the limit where problems might start to occur… But I’m not going to investigate that today haha :stuck_out_tongue: )

So I guess I’m off to the Onshape forums now, to ask why they they are exporting with so many points, or if there’s a way to export a more simplified version. Yeay.

Thank you @Jules.

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My pleasure, but the nodes were @eflyguy’s find. He deserves the thanks on this one.

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No, the OP commented on that first, while I was taking a look.

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Neither one of us was needed! :smile:

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Thank you to @eflyguy for confirming what I was seeing.

@Jules, your idea that it might have moved was one I did not think of and was a good variable to eliminate in my tests.

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I’m sorry that you ran into trouble when trying to print this design and got unexpected results. I’m glad to see that the discussion here on the forum was helpful! Something which might help would be to try simplifying the paths in either Inkscape or Adobe Illustrator. Will you please let us know if that helps your design to print correctly?

@ivan1 Simplifying the shape to a small number or minimum of nodes works perfectly, of course. Looks like I’ll need to add an intermediate step to my workflow and use “Smooth Curve” in Affinity Designer to reduce the number of nodes.

Side note: I would happily export DXF files from Onshape which wouldn’t need any simplifying, but Glowforge (as well as Affinity Designer) unfortunately can’t read DXF files. Please add “ability to read DXF files” to the future features hopper if possible. Thank you.

It’s been on the list since before the machine was available.

In prior discussions on this, it appears DXF is not standardized enough to be suitable.

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It’s an open specification that has been used for 25+ years. I wonder why GF wouldn’t consider that standardized? :laughing:

Like I said, search prior discussion. There’s significant variation that causes issues, per my recollection.

i.e. Dxf compatibility talks specifically about it being “gnarly”…

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… and here’s one talking about how DXF doesn’t always play nicely between CAD software.

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Appreciate the links, thank you.

Thank you for updating us! I’m glad to hear that simplifying the shape to a small number of nodes helps to decrease the behavior you’ve been seeing. I appreciate your feedback regarding DXF files. I’ll make sure that it gets back to my team.

I’ll close this thread for now, but please don’t hesitate to reach out to us directly at support@glowforge.com if you run into any more trouble. We’re here to help!