Purpose of Multi Uv Sets or udims

dar0005

Hello, I would like to know the purpose of using multi uv sets and or udims, I believe they are used to allow separation of uvs of larger parts of a mesh from smaller parts and having a texture set for both and for the  smaller parts could be enlarged in the uvs to allow more detail on but on not sure if that  is the use of them. Can someone please explain? Thanks

throttlekitty

They simplify shader setup, some of the specifics depend on the software, and they're more useful in film or offline rendering. You're correct in their use, you basically get more UV space to work with to split across different textures in a set. A shader only needs to be directed to the first texture in the set; the rest are picked up automatically via the naming convention. Plus, you can have a single shader across a set with no effort, instead of the typical scenario of needing a duplicate shader for each texture, all the shader settings are in one place.

musashidan

I believe Udims (and Mari itself) were developed at Weta digital as a means of authoring  massive texture resolution on vfx assets in a very simple and artist-friendly way. So, for imstance, a hero close-up shot might have 100+ x 8K maps per channel.