A problem with cutting out a shape imported from an SVG file


I have a problem with cutting out a shape imported from an SVG file. This is what the shape looks like in the project and what it looks like in the preview and after cutting out:

I tried to disable the “Optimise Cut Path” option but it didn’t do anything. Is there any way/setting to cut this shape correctly?

A SVG file:

The construction of the shape seems to be causing some issue for LightBurn. The ellipse is made up of hundreds of thousands of extremely small line segments. Between that and the relatively small geometric size of the shape is resulting in the distorted preview and burn.

While I suspect LightBurn should be able to interpret the shape correctly an easy work around is to optimize the shape so that it’s easier to interpret. Select the shape and go to Edit->Optimize Selected Shapes to simplify the shape. This may take a while as you’re dealing with so many nodes.

Adding @Rick here to comment on potential issue dealing with large numbers of extremely short line segments.

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It’s working. Thank you for help.

A blue layer - the original shape imported from SVG.
A red layer - the shape after optimization.

and preview with both shapes.

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Just to add information and perhaps a faster method:
Select your shape and Arrange → Break Apart

Then select Edit → Delete Duplicates
wait a few seconds and click yes and do a Preview.

Forgot to mention to Auto-Join shapes and then Optimize shapes.

Worth checking the program you’re using to produce/export SVGs for optimization options.
Also check this option in Lightburn.


Thank you very much for your reply. Your method also seems to work, however it removes too much and the outline of the shape becomes a dashed line.

I’m testing script making a x/y kerf offset:

Thank you for your efforts and help.

This is apparently a problem with a piece of code that’s trying to remove “insignificant” results from the output. Since every one of the line segments was extremely short, nearly all of them got removed.

To avoid a really technical explanation, the code was taking a shortcut it shouldn’t have, and has been fixed. The new result with your file looks like this:

Your file is insanely built - there’s no need to use 182,000 points to describe a small circle, but it now works regardless.


You may have already played with the Kerf compensation LightBurn provides, but wanted to mention here for anyone looking for such to assist.

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