Hello, I am working a character model and I realized that head of my character is way more complex comparing to the rest of the body, more textures and masks, so it make sense to have a separate shader for it.
Also I have UDIMs on my model, so the question: is it possible to have one shader for the head and the rest of the UDIMs rendered by another shader in the udims workflow ?
If not, what other options do I have, like separate material / shader for each separate tile?
I’ve checked how metahuman is dealing with this, but they just have separate meshes for body and head, not my case.
Supposed to be a common problem, but I can’t find any solutions at all. Any suggestion is greatly appreciated.
You can have the polygons in the head render with a different material, yes. How you do this depends on which DCC tool you use, but it should be possible to select certain polygons and assign a different shader in there. In this case, it sounds like you would want to select the UV islands for the head and assign those polygons a different shader. Unreal will respect this as a separate material slot on import.
From there, the materials can sample from the same UDIM set if that has already been created. The body material simply won’t sample the head UDIM tiles as it has no UVs in that space. The same is true in reverse for the head material. The virtual texture system should take care of this transparently.
Do be aware that two materials will increase the draw call count for the object as each draw can only render a single material.