# Booleans/Welding/Subtracting help please

So I have a shape (in this case, a bear) that I am trying to engrave other shapes (in this case, trees) onto a portion of before cutting out the bear outline.

For some reason, I can’t figure out for the life of me how to get Lightburn to essentially chop the trees off at the outline edge, but retain the shape as separate. I’ve tried all the Booleans and tricks I can think of, I wasn’t sure where else to check as this is a pretty specific problem. I’ve attached a screenshot of what I have now… the trees will be “filled” and the bear “line”(cut).

What do you mean by “but retain the shape”?

Boolean operations change both inputs. If you need to keep one of them (or both) use Ctrl-D (or Edit > Duplicate) to create an in-place copy to use for the boolean op.

In this case, I think what you want is to duplicate the bear, then select the trees, then the bear, then do Subtract.

1 Like

Subtract? You mean boolean difference? Also, I think you want the bear first, then the trees.

Trees are a group, bear is solid outline.

Select the bear, then the trees, then Boolean Difference.

Please excuse the rudimentary wildlife scene.

Boolean difference, yes. It works like “A minus B” - She wants to keep the trees outside the bear, like this:

Or, in my case, the egg.

Oh I’m dumb and can’t read I guess. It’s hereditary.

Sorry if I didn’t explain very well. I think duplicating the bear probably is the correct move, but then when I go to “fill” the trees, won’t the entire bear fill?

Also, the trees are numerous shapes, not one continuous. If I group them as one shape will it change things?

It should be fine - You’ll have to group the trees into a single group so the boolean will work, but otherwise that should be fine. It won’t affect the fill.

Closer, how do I invert this so the fill portion is the trees not the bear shape?

Select the trees first, then the bear. You’re saying “I want shape 1 with shape 2 subtracted from it”.

Selected trees, then selected duplicate bear shape:

And here’s the result:

Oooh - you want the trees in the bear… I get it.

In that case, make the trees black, and the bear red again. The subtraction (boolean) sets the result to be the most common color used in the inputs.

For that, you’d select trees then bear, then choose “Boolean Intersection” to get this:

Is that what you’re after?

Yes, trees in bear. Also thank you for all your help!

Regardless of which order I select them in, then use the Boolean Intersection, the result comes out the same (below). I tried red bear then black trees, then black trees followed by red bear and got identical result with Intersection.

That is the correct result, you just have to duplicate the bear shape first. Both inputs are “used up” by the boolean operation.

Ah-HA! Got it, thank you very much! I love learning new stuff!

1 Like

I spoke too soon. Here’s a wrench for ya… what if I want different trees to be different layers (for different power settings to try and achieve a non-uniform look on wood) ? Obviously then I can’t combine them into one shape… and when I try to select them when layered different it won’t let me Boolean Intersection. I grouped them as one shape (even when different layers) and when the Boolean Intersection happened it changed them all to one layer color. Thoughts?

1 Like

Break the overall process described above into several pieces, designed for each layer you want (different layer for the different power levels you want to cut). In other words, do the exact same process multiple times, isolating the desired sections and place them on a different layer. Repeate the process for each section until you have the complete presentation.

1 Like

To change the color after the intersection, un-group them, pick the bits you want, and click one of the layer colors in the bottom palette.

No sooner than I had typed I think I figured it out. I duplicated the bear, selected one tree, and Boolean Intersection’d. Then I duplicated the remaining bear shape, selected another tree, again.

As a suggestion from a dummy like me, a cool thing would be a short little animation that pops up with a blurb about the Boolean functions, with one of those boxes “click here to never see this again”. I use them semi-seldomly and despite best efforts, seem to need to re-learn the little tips and tricks each time. Thanks!

We have had discussions about these types of helpers and adding links to video tutorials. These chats continue but this work will require resources we are currently dedicating to development and feature additions.

To help you today, hover over any tool and select F1 to bring up the appropriate help resource, including a link to the relevant video tutorials.

2 Likes