Meaning of entities named "Difference" in Outliner?

I’ve been using SketchUp Pro (Version 23.1.341) on MacOS for a while now, and I’ve noticed that sometimes groups or components I’ve created get lumped into one or more top-level items in the Outliner, all named “Difference”.

Here’s a screenshot of the Outliner for one project where 3 distinct “Difference” items appear:

I haven’t found any obvious pattern to when this happens. It typically disappears after a time, i.e., the “Difference” outline item goes away, and the previous top-level groups/components reappear. I also don’t see any obvious pattern to when that happens. It doesn’t seem to happen to every modeling entity, nor to every change I make.

Since the “Difference” items take the place of part of the outline structure I set up, I find it annoying, particularly since it’s hard to tell which “Difference” entity corresponds to which model entities.

Does anyone know what’s going on here? Can I turn this behavior off entirely?

When you use the native Solid Tools, the resulting modified objects become groups called Difference. You can rename them if you wish. If, instead, you use Eneroth Solid Tools or Bool Tools 2, the objects keep their original name and if they were components to start with, they’ll still be components after the Boolean operation completes.

Don’t use the native Solid Tools.


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Oh, thanks! That explains it.

That said, I really didn’t expect that behavior from the Trim tool (which I was using here) in particular, since it’s intended to leave the original cut-into-solid and the cutting solid intact after the operation.

That has been the behavior of the native Solid Tools since they were introduced more than a decade ago.

The fastest way is to use another tool like Dave mentioned, I use Booltools from mindsight studios, it’s a paid plugin but Eneroth’s plugin is good as well. There’s a way to keep the name and attributes of a component using native tools but it takes a bit more time, you must copy the trimming object, get inside the group or component, make it a group, paste in place the object you copied, and make the Boolean operation, it sounds tedious but if you have shortcuts assigned to make all those things you can do it in few seconds. I’ve assigned the letter V to paste in place, Shift G to group, and H to trim.

One could also right click on the (formerly) object now called ‘difference’, choose ‘Make Component’.
It then suggests the name it had prior to the Trim action.
If you choose that, it will pop up a question ‘A component with that name already exist, do you want to replace?’
Yes would replace it for all instances.