I have a question about specific uvs that have textures. I would simply like to move uv shells into new udims. The layout node reorganizes the shells and thus the texture assignments. I can use a uvtransform to move a set of uvs to a new udim space. But it's not really a udim without attributes so the shaders understand assignments by udims? Maybe I'm overcomplicating it and there's a simpler approach. But I looked in the geometry spreadsheet with a uvlayout to see if I could see where the attributes were landing but didn't see any udim attributes. Any ideas on this? Thanks in advance and hope that makes sense.

UDIM is computed purely from v@uv attribute
https://www.sidefx.com/forum/topic/56984/#post-255187 [www.sidefx.com]
and similarly you can shift any uv island to any UDIM you want just procedurally by altering v@uv attribute to contain correct offset for the UDIM you want to place it into

so essentially if you are already offsetting UVs manually to different UDIM tiles then the renderer will recognize those UDIMs automatically from v@uv attribute and you dont have to do anything extra

Thank you Thank you! This is exactly what I needed to know.