Can Not move Vertices vertically

sKetchup 2022 on Wind11
I can not move any of this geometry on blue axis. MoveTool>click+[arrow up]… I can move them and x, y locking works but no z… like it was a DC component with fixed z value… Just it is a simple geometry… was complicated geometry but I deleted everything else exploded groups and comps, purged clicked fix problems in statistic tabs… reopened file and it persists. I can select one triangle face and move it on Z axis but all will move together.

I guess it is some file error… Can delete and redraw … it is not a lot but am very curious is there a way to fix it without redrawing…
tmp1.skp (130.5 KB)

I can’t explain why but is related to the face having four edges.
If you move one vertex it works again.

Part of this simple model is the most convoluted example of the long-standing “bow-tie” bug I have ever encountered! I haven’t a clue how it was generated.

The skinny triangular face at the -red side is ok (one of its edges is soft and smooth, so you see it only if view hidden is on).

The rest makes up a tangled mess! It all is captured as a single face with normal vector +z in the model database. All the vertices of the face are at z=4490 exactly; non-planarity is not an issue.

The face starts its outer loop by following three sides of the skinny rectangle at the top, starting at vertex [~4961, ~6397, 4490], going from there to the upper right vertex at [~5609, ~6517, 4490] and thence to [~5605, 6510, 4490] and then [~4957,~6389,4490]. Because this loop is left-hand order with respect to the normal (we’ll see how it gets closed later), SketchUp’s rendering and selection logic treats it as a “hole” and does not fill it.

The loop then goes down the edge from that corner to the top of the large triangle at the bottom at [~4991, ~6260, 4490]. The loop then traces the outline of the large triangle in right-hand order, going down to [~5070, ~5928, 4490] → [~5311, ~5984, 4490] and then back to [~4991, ~6260, 4490]., closing the large triangle.

Then it retraces [~4991, ~6260, 4490]->[~4957, ~6389, 4490] in the reverse direction from previously!. Finally, it completes the loop by returning to [~4961, ~6397, 4490].

So, we have the double oddities of a left-handed loop at the top and an edge that is used twice in opposite directions by a single face!

Evidently all this weird geometry causes the problem with moving vertices in the z direction until some other edit is performed that causes SketchUp to “heal” the defective face.

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I love Your explanation … though to be honest I can not understand how sort of complicated geometry stops moving vertices with an arrow pressed…till now I knew only about glued components that they can block (or ignore) arrow forced direction… moving vertex should just force the face to triangulate no mater what and … this one behaves like it was glued… Or maybe it is an error in triangulation process… it can not triangulate correctly … there is an error returned… face remains not triangulated so it doesn’t allow to move away from the face… Error would be understandable since it would try to draw two triangles between two edges which are actually the same edge just in opposite order…
I can understand why sometimes the same edge has to be used twice in opposite direction…
but how it gets the idea that there is an actual face between them I don’t know… But maybe it is like with math… how people think that there is a solution to an equation = 0… it means there is nothing… there is a solution just it is non existent one… There is a face with area = 0

With no access to the proprietary code there’s no way to know how a geometric oddity such as a bow-tie might break SketchUp’s logic. I agree that preventing z axis movement is very strange. Maybe the bow-tie somehow tangles with the auto-fold logic.

It is quite common for an edge to be used twice in opposite directions. It is necessary so that an edge can be shared rather than having two edges exactly on top of each other. The real issue with your original model is that the long rectangle has somehow come to be traced in left-hand order, which causes SketchUp to treat it like a hole in the face it is entirely outside.

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