"Your recent operation has caused visible geometry to merge with existing geometry on a hidden layer"

I’m a new user and coming from a AutoCAD, Alibre/Gemagic and Solidworks background.
So layers are causing me difficulty.
Of course with my back ground I instinctively wanted components on different layers and made components to construct my first model.
Un-instinctively I did not create my components on Layer0.
I created the roof components on a roof layer.
I created the frame components on a frame layer…ad nauseam.
Even if I created a floor decking component on the floor joists layer after creating a floor decking component I would dutifully change the layer of the newly created component in the component info dialog layer to the the what I thought was the appropriately named layer, in this case floor decking layer.
Now whilst doing subtract and trim operations I’m getting the ye old “Your recent operation has caused visible geometry to merge with existing geometry on a hidden layer”.
I reckon this is bad as the warning is likely there for a good reason and all the help files say in order to avoid this error/warning to always create all the individual entities on layer0, always make layer0 the active layer etc.
But no one really explains why this is bad.
No one really explains where these leaping/merging entities wind up or how to figure out where they came from and where they are now located?

Which makes me think this about the advice scattered around about keeping all entities on layer0.
So if you create all you entities on layer0 I can see how they would not be merged to another layer because they have no where to go.
You create everything on layer0 and everything stays on layer0
Seems to me they if they are all on layer0 to start with and simply stay put wouldn’t you still end up at the same place as merging everything together.
Seems layers in sketchup have nothing to do with an actual layer, instead of the layers dialog it should be called the the visibility dialog???
But if that were the case why is geometry merging from one layer to another?
If it can merge then geometry has to be able to exist on separate layers in the first place.
If this is bad then why even allow the user the change the layer of any entities what is the benift[s] of having layers other than visibility?

Whilst Greping around for answers I found this tidbit
Note: Assigning a different layer to a group or component doesn’t affect the layer assignments of the individual entities within the group or component. If you want to assign new layers to the entities within a group or component, you must edit the group or component, select specific entities within the group or component, and then assign a different layer to the selected entities.

So from that it would appear that sketchup does have layers in the “layers” sense of the word and you can in fact change the layers but if you do a subtract or trim remaining entities will be sent to/merged with the layer[s] that comprise the first solid used in the operation or maybe to some mystery layer…layer0 possibly?

Why is “Your recent operation has caused visible geometry to merge with existing geometry on a hidden layer” bad or a problem to be avoided like the plague?

Apparently merging geometries are bad so now that I have created my components on every layer in my model how do I fix this problem?
Start over?
I suppose I could explode every component and change each entity to layer0?
Is there a clear answer to any of this other than create everything on layer0?
My head hurts from the top layer to the bottom layer.

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I don’t think posts here are supposed to read quite like James Joyce. Rather than your stream-of-consciousness musings and ruminations, which put me in a trance-like state about halfway through, if you were to ask a specific, succinct question of fact, you might get a useful answer.



Why is it bad to create entities on any other layer other than layer0?

Well, I found your post to be entertaining, @sergeyisaleftwingnut.

Ideally, in SketchUp, all raw geometry should be developed in Layer 0. Be aware that edges (lines) will stick to adjacent geometry unless isolated within a group or component. Keep Layer 0 as the active layer and move selected group or component entities to other layers as desired.
Also be mindful that layers are used primarily for the purpose of controlling visibility in SU, somewhat unlike how this category is employed in other types of professional graphic softwares. Have a look at these links for a bit more clarity:

Before adopting SketchUp/Layout as my primary electronic design tools, I too used a variety of cad applications including Acad, Revit, Vectorworks, and ArchiCad…so I can feel your pain.

Now, that’s something I can work with.

The problem is related to the behavior of raw geometry in SU, which is different from just about any other program I’ve seen.

  • When two lines cross, they cut each other
  • When two lines contact each other, they stick together.
  • When two lines are exactly congruent, the second line is “absorbed” by the first.

Since layers are used in SU for the single purpose of controlling visibility, if you spread raw geometry across multiple layers, inevitably there will come a time when you turn off the visibility of one or more layers containing raw geometry, and then the fun begins. You will thereupon find it impossible to draw certain edges (because they keep getting swallowed up) or find that edges you draw keep getting cut unexpectedly and so on. It’s pretty confusing.

Keeping all raw geometry on Layer0 is a form of self-imposed discipline that allows you to keep track of raw geometry and avoid unintended interactions and other pitfalls.

Visibility should be controlled at the level of the topmost group or component in which raw geometry is contained; the visibility attribute affects everything below it in a hierarchical structure. While I have not personally run into this situation, we have seen many reports on the forum of cases where switching off a layer still leaves objects on that layer visible. It invariably turns out that the users who report this have spread geometry across layers, throwing SU’s visibility logic off kilter in some way.

I don’t think most user manuals I’ve seen go into the various possible adverse consequences of disregarding explicit instructions given in the manual, do they? That would make them several times as long as they need to be. They just tell you what to do, and if you do something else, you can probably expect it not to work right, if at all.

For someone here on the forum to fully answer your question about all the bad things that can happen if you violate that rule, they would have had to systematically and repeatedly violate it themselves and observe the results. However, motivated by self-interest, most users try to comply with the rule once they find out about it and live happy lives thereafter.


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Layers in SketchUp are used to control visibility.
If you assign layers to Groups or Components then you can switch those layers on/off and their contents will appear/disappear in a controlled way.

Layers in SketchUp are NOT like CAD.
They do NOT separate geometry.
For the avoidance of doubt - geometry is faces and edges [aka ‘lines’].
You have probably noticed that if you erase an edge that forms part of a loop of a face, then that face disappears too.

Imagine for a moment that you do not follow the received wisdom of the ancients...

You reassign the layer from some of your faces, and also reassign a different layer for some of those faces’ edges.
If both layers are ‘on’ then erasing an edge will also shown you that the reliant face goes too.
So if that was done in error you can immediately undo the edit and recover the lost geometry.
BUT let’s imagine that you switch the faces’ layer ‘off’, but leave the edges’ layer ‘on’…
Now you might erase an edge and think that nothing else is affected…
Because when you switch the faces’ layer back ‘on’ any faces that relied on those deleted edges have also gone.
And now it’s probably too late to undo the mess !
Layers do NOT separate geometry when they are switched ‘off’, they just affect visibility.

So ignoring that simple truth is a sure fired route to acquiring a bad temper and potentially eventual insanity…

So the simple mantra is - always model your ‘raw’ geometry - faces & edges - on Layer0 [ and always leave Layer0 as your ‘active layer’ ]: make groups or components containing that geometry, and assign layers to those yo control visibility.

Another benefit - geometry that touches ‘sticks together’ - this can be useful, but in other circumstances you do not want it - using groups/components separates the geometry and so it no longer ‘sticks’ to geometry in a different ‘context’…

Remember that if you accidentally assign a layer [other than Layer0] to some geometry, then it’s simple enough to select that geometry and use “Entity Info” to reassign it to Layer0.

Open the Layers Manager … Window > Layers

Delete all layers except the Default Layer 0, which you’ll notice cannot be deleted.
As you delete the layers you’ll see this message…

Hi Gully
Sorry to go all James Joyce on you with the first post.
I was truly dazed and confuzed.
As TIG says below “So ignoring that simple truth is a sure fired route to acquiring a bad temper and potentially eventual insanity.” …amen brother!.
Strange things were happening all around me with no seeming explanation the more I did the worse things became.
There really should be a warning label for folks that come from a different layer construct.

Okay so I think I know how to stay out of trouble…thanks to you and the other very helpful posts thus far.
The reason I wanted to know why this was bad was I was trying to figure out how to unscrew what Götterdämmerung I had wrought.
Looks like if I follow Geo’s suggestions below I’ve got that under control.
But now I can’t get it in my mind (or out of), why you would ever want to draw something on another layer other than layer0 or why the ancients in their wisdom would allow one to draw on other layers but if it wreaks all this havoc?
Why not have a visibility & color traits for components and no layers?
So I’ll try and boil it down to the non Jame Joyce version.
Why is it useful to be able to move geometry to another layer?

To seggregate your model into manage parts, you wrap Layer0 geometry with either a Group or Component wrapper(s). Then if desired/needed, move the outer group/component(s) wrappers to different Layers in order to control what is visible in your workspace.

One way to do that is to set up different Scenes. To each Scene, you can save which Layers you want to be visible (be sure to Refresh the Scenes as you go.)

I suggest that you do a search in the “Knowledge Center” for layers. There should be enough information and videos there to clear up your confusion on how SketchUp layers work. Just a thought.

After thinking about it some more I no longer believe in SU layers anymore…does that make me a layer atheist??
(I still believe in Santa Claus)
I believe that layers should be renamed to visibility scope…can you hear me oh ancient ones?
When you are creating a new layer you say to yourself I am creating a visibility scope for selected group[s] or component[s] not a layer then this will help you to understand what is happeneing.
And even if I lose my sanity and create geometry in another visibility scope other than layer0 visibility scope I now know the geometry never goes anywhere (There are no more layers in my world so there is no where for the new geometry to go).
I have only created geometries in a particular visibility scope but they are free to interact with other geometries but only when outside their group or component. (This is an important concept)
What frees geometry from its group or component so it can interact with other geometries?
I’m guessing a solid operation trim subtract union etc. frees the geometry from its group or component leaving it free to interact with other geometries as the ancients so ordained.
Whether the geometry is visible or not makes no difference to a geometry, a geometry has got to do what a geometry does and that my friend is interact with other geometries.
Whether a geometry does it in the middle of the road (visibly) or not makes no difference to a geometry.
So the reason it is bad to create geometries in a scope other than layer0 and the reason you must always keep layer0 the active layer i.e. visible (another important concept) is if you perform an operation that sets a geometry free you want to set it free in the middle of the road.
That way you get to see what happens and there are no sneaky results/ black magic/evil spirits to make you doubt the wisdom of the ancients.
Does that make sense to anyone?

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Intersect Faces > With Model while within the editing context of a Group or Component.

Sure, it makes sense. But the bottom line in all this ranting is that having climbed the learning curve on some other CAD, you want SketchUp to meet you there rather than to have to learn it too.


GOOD THING SKETCHUP HAS ERROR EXPLANATIONS. I just did undo after the push-pull operation and searched for this subject in the forum. I will create all new components in layer 0 then change them to a new layer. Please let me know if the undo has cleared the problem. I’m guessing I’ll find out in 15 minutes.

No such luck. I flattened the surfaces by doing the undo push-pull, selected the ENTITYS and moved them to layer0 and got the same error when I tried the push pull operation again. I imagined that layer0 was placed at an infinite Z coordinate but I’ll have to try redrawing the ENTITIES on layer0?

The error message indicates there is some raw geometry placed on another Layer that was hidden. That hidden geometry was not placed in a protective group/component wrapper. The new geometry was being manipulated in the same space as the hidden geometry, so it merged.

Go to Window > Layers and make the hidden Layer visible to see it.

To fix: all raw geometry should be on Layer0. Keep Window > Entity Info open while modeling. You can move all selected raw geometry into Layer0 from the Entity Info window.

Select model part you want to keep together as a unit and place it in a Group/Component. Select it > r-click and choose either make group or component.

Select the group/component and move it (the group/component container) to another Layer through the Entity Info window,

Share the model if you want someone to look at it.


Thanks catamountain,
I got all that last night. Even though I had grouped or made components of most all of the elements and layers and in fact locked the major ones. Only one layer collided. Took an hour to redraw it on layer0. Then push-pull operation led to offset limit which was fixed by holding down the Ctrl key while executing the push-pull. No ENTITIES appeared to be in the way and I don’t know of any constraints on offset that I set myself.

Also, on closing the file last night I saved it when asked. When I opened it from it’s folder I had to sort the folder by date to find the latest version and that file was one move short of the closing save? I know because I moved the floor plan Xref .DWG up from the origin by 3’. It was still on 0 in the Z axis/blue?

Save/Save-as and incremented saves (every 5 mins) seem to be bulking up the folder while not actually recording the last save? Hence the need to sort by date. There should only be two files in that folder. Not six. One .SKP and one .SKB. There must be a way to save exactly what you want and to where. Dropbox and AutoCAD 360 as well as the original file folder before exiting the SU Pro 2015 program.

Thanks again, catamountain, group or component before speculating SOLID?

I might suggest a tooltip on-hover or mouse-over indicating component, group etc.

[quote=“Heinz, post:18, topic:8528”]
I might suggest a tooltip on-hover or mouse-over indicating component, group etc.
[/quote] Select it and Entity Info tells you - leave its dialog open, it’s a valuable source of information, and allows editing of many details too…

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Good answer! I think one forgets that Sketchup does things differently, and one should not try to make it work like Acad, ArchiCad, Revit or whatever. Moving from a package like these to SU is like move from PC to Mac - its different, and the sooner one understands and accepts it, the smoother things will happen. I too struggled in the beginning, and when taking the time to understand the thinking behind SU, then things go a lot quicker.