Inconsistent behavior with CUT

Hi All. Does anyone have any insight into how LB identifies vector segments with the cut tool?

I haven’t noticed a pattern or vector characteristics that control whether the cut tool isolates the candidate segment to what I’m hoping for, versus when it ignores that crossing vector. When the latter happens I have to insert nodes at the intersections and either delete the node segment or switch back to the cut tool.

I’m working my way around this map, trimming the overlapping vectors (overlapping a rectangle frame). Most work just fine, but several of them don’t work. Here is an example. Note the proposed cut operation extends past the intended vector intersection.


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Can you share the file with us so that we can take a closer look?

Here are the trim shapes tool docs: Trim Shapes - LightBurn Documentation

It’s an interesting question that I’m also interested in. I use the scissor tool a lot and like it very much, but like @tbeaulieu I experience the same malfunctions sometimes and haven’t been able to find a connection that explains it.
It’s also difficult to provoke the phenomenon, in my example of shapes that are both closed and open, all segments are (can be) correctly cut at the nearest intersection of another line.

I made this test in 30 seconds and it shows the issue. Hover over the top of the shape.
CUT DEMO.lbrn2 (17.2 KB)

You can see there are open shapes.

The cut tool will prefer if you have a closed shape, since the shape is open, it is not clear what side of the shape is inside or outside.

In this case using edit nodes tool is best. You may need to add a point to define where your line stops and starts so the cut tool knows where to snip.

Edit nodes: Edit Nodes - LightBurn Documentation

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I have tested your file and it “works” as you describe it and is the same as what I observe from time to time.

That’s an option, but in my example there’s no problem with non-closed shapes, it cuts fine, so no real logic in it.

CUT DEMO-2.lbrn2 (12.3 KB)
(there are no closed shapes)

What I usually do in problematic trims is Break Apart first and Auto Join at the end of operation.

I just think the cut tool should always stop at vector intersections. It’s what people expect and it’s how it mostly works.

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Something strange with your shapes. I create a line at the intersection:

Low zoom seems ok.

If I zoom in more:


not ok.

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I’m going to go out on a limb here and say no… no, there is nothing wrong with the shapes. We both just reproduced the scenario in 30 seconds. I’m going with … it’s the app. LOL.

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