Laser Path Optimizzation with multiple part layouts

Hello there!

First question here, I hope I didn’t mess up!

I’m trying to layout some symmetrical interlocking part so that the finger joints cut of the simmetrical parts form a single shape. (img for reference, the symmetrical parts have different colours only for reference purpose)

I’m designing all the parts in fusion360, then exporting every single “surface” as dfx, inporting them into lightburn, then duplicating and mirroring the part I need.

I’d like the laser to cut out every hole first, and by holes I mean not only the red shapes, but also the paths highlighted in the picture (I’d like to have a clean linear cut on those “holes” first, instead of having the laser following every corner of the shapes potentially showing a more burnt look on each corner).

Is there a setting to achieve the same result, or even a way to select only the lines I intend to cut first to set the priority manually, even if they are part of two different closed paths?

p.s. I already selected the option to remove overlapping lines in the optimizzation window

Thank you in advance!



I don’t think there’s anything that will make LightBurn treat the highlighted sections as a continuous single inner shape.

In general, inner shapes can be prioritized through “Cut inner shapes first” Cut Optimization. However, I don’t believe this will override layer order. Since your red shapes are in a different layer make sure the red layer is first in cut order or put the red layer on the same layer as the others.

In your particular case, I normally don’t advocate for this but if you wanted to attempt to force that section to cut first you could break apart the design, then select only those line segments that make up those sections, and then using “Cut selected graphics” cut those areas first. Based on the individual line segments you’ll likely get a series of line cuts rather than one continuous cut. You could alter the design by joining those line segments to actually create a single continuous shape for those “holes”.

Yes, Reds are cut before Blues (and yes I know the default for LB is the opposite, I just happen to use a Fusion360 extension that uses that color order)

I tried with the “cut inner shape” option but the preview still draws another path. But again, if taken individually, all those parts have no inner shapes. It’s just this layout that makes “holes” also closed paths. So I’m not blaming the software at all for not recognizing it!

Also, it’s not mandatory for me to use that cut order, I’m just curious to learn a) if something like that is possible without preparing again the dxf files outside from lightburn, b) if it’s something THAT desirable at all from your point of view!

Thank you again!


It looks like you have 5 layers.

You can move the layers around on the Cuts/Layers window and then cut them in order - so this may be simple.

You could draw (copy) or move all the inside shapes on/to the red layer.
You can tell Lightburn to Cut Inside Shapes First in the affected layers
You can add knock-out tabs to hold the inside shapes in place so they cause no issues.

fast way… Copy everything. Paste the copy off to the side out of the way. Move all of that copy to the red layer Delete all the stuff that isn’t an inside shape. Go back and trim the original (if you feel a need to - you don’t have to - you can just leave it) Move your inside shapes back into place and cut them first. :smiley:

You could modify the design within LightBurn itself without a roundtrip outside of LightBurn. Especially since the changes I was describing are more a hack than what you’d want in the actual design.

I would always welcome more capabilities but understand that there are priorities.

I tried condensing all the infos in a single image, but I realize it was a bit confusing!

The 4 different layers colors for the parts were just a way to try to show the couples apart from each other. My actual project have only 2 Layers, the inner cuts (1st layer) in red and the outer cuts (2nd layer) in blue.

I’m attaching a picture of a single part. The lines that form the inside shapes are not connected at all in the design, and form a closed path within the part.


wich function could I use to break those designs apart? (picture of a single part attached in message above!)

Thank you again in advance!

Arrange->Break Apart will separate all the individual line segments at existing node joints. If you need to introduce nodes you would need to do that using the Node Edit tool.

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