An error message I don't understand

I get this message:
‘Your recent operation has caused visible geometry to merge with existing geometry that is hidden.’
I’m drawing a building model and have a lot of tags turned off so I can work in one at a time. I would like the portion of the drawing I’m working on to be distinct, so it has clean lines and faces in and of itself. Any direction from you smarter folks out there?

That implies you are using tags incorrectly. ALL edges and faces should be created and left untagged. Only groups and components should get tags. You should be creating groups and/or components to prevent different parts of your model from merging. Tags don’t provide separation.

It would be a good idea to go through the SketchUp instruction at

Thank you, Dave.

I am, like lots of people, fundamentally lazy about getting too far into some of these interactions, wanting, I guess, the simplicity of some of the early versions. I started using it when it was from “at Last”.

I’ll try some reading. Thanks for the reference.


Robert S. Bast, AIA
Bast & Rood Architects
PO Box 220, Hinesburg, Vermont 05461
o. 802.482.5200
m. 802.363.0871

Other than the name change from “Layers” to “Tags” nothing has changed regarding the rules about only giving components and groups tags/layers has not changed. It’s always worked this way.

I also started using SketchUp while @Last had it.

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@rob.bast Have you now come to understand the message that SketchUp displayed? If not, here is my take on an explanation. A SketchUp model is fundamentally composed of edges and faces (among various other types of entities). When a new edge and/or face is created within an editing context (the top-level model, a group, or a component) that already has edges and/or faces, the new entities will merge or interact with the existing entities that make contact with the existing entities. This is how to build up complex geometry from primitive elements, one of SketchUp’s fundamental tenets. Such merging or interaction is generally readily apparent when all the entities are visible.

Edge and face entities can be associated with a tag (though this is strongly discouraged, as mentioned by @DaveR). When the corresponding tag is set to invisible or hidden, the associated edges and faces vanish from the model viewport - but of course they are still in the model. If a new edge or face is created that contacts the existing but hidden entities in the same context, the standard SketchUp rules for merging or interacting continue to apply. The interactions between hidden and new visible entities is generally not obvious, so SketchUp displays the message you reported to remind the user of what is happening as edits occur to the model.