Zig Zags on Offset Shapes (Bug?)

Odd issue that is not very consistent, but when doing an offset on some of the circles it will make them zig zags. The same circle selected by itself is fine, but when multi-selected with other shapes it often will do this. Any ideas

Lightburn Issue 2b

Lightburn Issue Zig Zag Offset Shapes.lbrn (1.7 MB)

To recreate, select all the red layer objects and do an Outward offset.

NOTE: Ignore the q’s, those are just my screen capture tool.

The Offset will be applied to the entire selection. Could this be the issue you are saying is an “Odd issue that is not very consistent”? If you select a different grouping of shapes, arranged in a different pattern, the Offset will be calculated differently. While the first example may look correct, the Offset is not applied to each ellipse in this selection. It is applied to the shape of whatever is included in your selection.

I think we’re talking two different things. The issue reported here that I’m seeing is that on some shapes (circles) when making an offset instead of making a nice, crisp larger circle “outside” we end up with this jagged shape. The file I uploaded has a red layer where this can be seen by selecting all shapes in that color and performing an offset. You’ll see some shapes do the jagged thing.

I suspect this is because that circle is “sort of” inside the loop shape, and LightBurn is treating it as an inside (hole) as a result.

For the purpose of cut planning, we try really hard to do inside sorting even with things like your semi-circle, so if your file was pre-tabbed, for example, things still sort inside to outside correctly.

For the purpose of offsetting, this is likely confusing it, so I may have to put that behavior on a switch, and let it completely ignore open shapes when using the offsetter. I’ll log it as a bug.

The other side works properly because the outer hole isn’t fully contained in the half-loop, so it gets properly classed as “outside”:

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Fixed for the next release:


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Excellent, glad you figured out the cause & are able to fix it. Keep up the great work, still loving LB every day!

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