Dude you don't know what favour you did me! This is the only option i found to bake out an id map for hair cards in blender. Its important for the unreal engine Hair shader and this is the best solution ever.
Needed to De-bug a Bit and Works Like a Charm - Love this more than Object Info Method cause it works in Local Space instead of Global Space or maybe it was Object Space... i am not Sure but the whole point is that it works from 0 - 1 instead of World Space 0 to +1 (When you go Negativees it doesn't work >_>) And also it brings some more consistency on some colors instead being 100% Random its Sudo Random which i love!
Really useful, thanks for this 👍. I'm using 3.5.1 and for some reason I can only render the vertex colour with Eevee, in Cycles its black. Will try it in 4.0 when its out.
Oooh, you saved my life! I rummaged through a lot, I didn’t find anywhere how to paint individual elements inside the mesh. What if I want to paint each face separately?