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Blender newb here, v4.1. I am attempting to build a tree procedurally from geometry nodes, learning from a couple examples like this one and this one. Honestly things are going great with the exception of this singular roadblock I can't overcome with all my effort. I am building a UV map for the bark. It works as expected except for one set of faces which is "stretched". I can see why but I can't understand why. For some reason these faces (which are coincidentally the first ones of this mesh from base to tip) stretch across the entire map's x coordinate whereas all the other faces are scaled appropriately and exactly like I'd expect.

I feel like has been right in front of me for hours on end but I can't see it!

Geometry Nodes Geometry Nodes

UV Map (inspecting the map after geometry is applied) enter image description here

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  • $\begingroup$ instead of circle for profile mesh, just use a spiral with height 0, sounds weird, but works $\endgroup$
    – Chris
    Apr 17 at 18:01
  • $\begingroup$ @Chris, that does in fact work. Interesting. It's ultimately a different mesh that looks the same but I'm also looking for the underlying understanding. Why does that work, or the curve circle not work? This is a simplified example that I need to apply elsewhere. $\endgroup$ Apr 17 at 23:28
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    $\begingroup$ @Chris & Brian: I think (but I'm not sure either) it works with the spiral because there you have a distinct start and end so that mapping the UV coordinates from 0 to 1 works better... $\endgroup$ Apr 18 at 9:27
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    $\begingroup$ @GordonBrinkmann Exactly! For example, the mapping is done as follows for a circle with four points: The first face extends from 0-1, the second from 1-2, the third from 2-3 and the fourth from 3-0. As the values of the point domain are interpolated here, you create an inverted mapping on the last face where the texture is squashed instead of stretched. To solve the problem, you would need a fifth point with index 4, which is at the same position as point 0. This is why the spiral also works, but this can lead to other problems because it is no longer a cyclic spline. $\endgroup$
    – quellenform
    Apr 18 at 10:15
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    $\begingroup$ @quellenform Oh yes, that's how it happens, you're right. Sure, in some other cases this can be a problem that the spline is not cyclic... the good thing here is, since it is converted into a mesh where vertices can be merged by distance if necessary this should not matter. $\endgroup$ Apr 18 at 10:23

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instead of circle for profile mesh, just use a spiral with height 0.

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