Is there any way to project a material onto a mesh and/or multiple meshes without changing the material of those meshes or messing with their UVs? Ideally with the ability to only effect certain channels, I.e. only project a normal map onto a piece of metal so it's base color/roughness showed through. Or say I wanted to project a mossy decal across a few different rock meshes and have the normal map for the rock meshes blend with the mossy decal normal.
We do this allot in Unreal and it's awesome.
The best I can think of is a conforming mesh with transparency, but this is obviously problematic in workflows, and doesn't pass through the underlying material channels.