Having trouble with closing shapes

I’m a new user and struggling to understand closing shapes.

If I draw a square then try to intersect that with a line across the corner like this
Screenshot 2022-01-07 134416

Then I want to remove the outer corner pieces, so i’ve been converting the line to a path then carefully inserting nodes at the intersect points then deleting the line I no longer need.

LightBurn tells me I’ve got 4 shapes that are open.

I then select all the objects and I’ve tried Close Path, Close Path with tolerance, and auto-join selected shapes but none seem to make any difference. I also tried grouping them first but then Close Path with tolerance says it found 0 open shapes, but still give the same error above when I try to preview the output.
Screenshot 2022-01-07 135747

If I zoom right in on the intersections there doesn’t appear to be any gaps.
Screenshot 2022-01-07 135533

I’m sure there’s something simple I’m missing so hopefully someone can put me on the right road.
Any help is appreciated.

Can you share the .lbrn file here please?

If you enter Node Edit, then drag the node to snap onto the other node, this will close that connection point. Continue for the remaining 3 corners to close the shape entirely. Try that and let us know if you are still not able to produce this closed shape. :slight_smile:

lease don’t take this the wrong way, but I’m sure that will work for him, but doesn’t that really defeat the purpose of the close shape function? I may be missing something on the close shape and close shape with tolerance, but I can never get those to work for me. Is there a tutorial on that because it would be great to have the function do it for you.

Close shape and close shape with tolerance are 2 variations on the same core function. Close shape only works on a very specific and narrow condition where you have a nearly closed shape that’s disconnected only at one joint. Meaning that all other nodes between segments of the shape are full joined. As long as the single unjoined pair of nodes are within overlap tolerance, the “close shape” function will join the nodes and close the shape.

The only fundamental difference with close shape with tolerance is that you are able to specify a wider tolerance where the unclosed pair of nodes are not perfectly aligned but this necessitates LightBurn making an actual change in the design: either by moving the location of nodes slightly or by adding a line segment that connects the unjoined pair.

Auto-join selected shapes is similar in that it’s meant to join segments but is functionally different. Auto-join selected shapes will join all the overlapping nodes of all independent shapes that are within the selection. So imagine you have a string of 4 lines aligned end-to-end so that they appear as a single line, but where each individual line segment is not semantically joined to its neighbor. By selecting all these individual line segments and then doing an “auto-join selected shapes” it will semantically join all the individual line segments into a single larger line shape. Note, that this is still an open shape.

You can take this farther by taking 4 lines that align to form the outline of a square, and then auto-joining them. Because they were properly aligned, the line segments individually will be joined and will subsequently result in a closed shape.

That worked great, I guess I assumed that the snap to grid would give LightBurn enough information to close the shape.

Thanks for the quick reply.

Snapping in LightBurn works differently than other programs I’m used to. Requires a bit of adjustment.

Also, for future reference if your goal is to end up with a closed shape it may be easier to accomplish this using boolean operations. Check out this mockup.




  1. select base shape you want to take away from
  2. add selection of shape you want to use to take away
  3. tools->boolean difference

This way you don’t need to fuss with node editing.


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