Forums Technical Discussion Quads being split into individual UV shells?

Quads being split into individual UV shells?

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AndreasStation
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I'm having issues with copytopoints creating individual UV shells from each face on the mesh, I don't know if this is just a quirk with Houdini or if I'm simply doing things wrong… In the image I've attached you can see what I'm talking about, the first mesh in to copytopoints has the original UVs with a reasonable amount of shells, and all the other copies are just a mess. I also attached a small sample of my project incase anyone want to have a closer look.

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mayaUV.PNG (122.1 KB)
roof.rar (49.1 KB)

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jsmack
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I'm not sure what you mean by UV shells. Copy to points doesn't touch the uv of the template geometry when generating the copies. All of the copies will share the same uv layout.
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AndreasStation
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If you look at the top left segment you can see that it has one white line passing through it, each white line indicates a UV cut. All the copies of the original mesh has been cut along every possible edge.. It doesn't make sense why that would happen.
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jsmack
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Looks fine to me. I only see uv cuts where the original had them.

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uv_island.png (612.6 KB)

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AndreasStation
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Yeah, I have the same result when looking at the UVs in Houdini but when exported to .fbx and opened in Maya the issue seem to occur.
Maybe the issue is how i export my mesh then?
Edited by AndreasStation - Nov. 20, 2019 02:52:13

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HoudiniUV.PNG (462.8 KB)

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jsmack
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In houdini vertex attributes are effectively all unshared, as each vertex stores a value, even if they are the same value. At some point Houdini's FBX exporter gained the ability to fuse vertices with the same values. Perhaps it is getting confused by the overlapping uv's and not fusing them. I'm no expert on FBX and try to avoid using it if possible. Perhaps a dev can chime in?

I don't have maya so I can't test the observation you are having. Does the part have unshared uv's when you export it by itself? It may be that due to how uvs are stored in Houdini, that they will always appear this way when exported.
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