UV Face Material ID ?

#1

Wondering; is it possible to make material ID based on UV island face selections ?

#2

if you need only a clown map type rendering at the end this could work with udims…

#3

UDIM don’t like you exclusively set a material ID based on some faces on an UV island !

#4

as i said if you need a clown pass you dont need IDs… what do you need the IDs for.?

#5

Correct me if I’m mistaken; a clown pass is based on objects, not surfaces. Suppose you have one solid mesh, whereas the characters shoes are modeled on his body, you want his shoes to have, similar to a material ID so you can render it out separately, that is my goal, unless you are trying to explain this all this time ? :slight_smile:

#6

a clown pass is like a material id pass… you get red color for the shoes to do some magic in post…

if you assign a material with differend textures per UDIM you could move the uvs to get the clown mask… all uvs on UDIM 1 will be red… all on UDIM 2 will be green… and so on…

#7

When you say move the UV’s, what do you mean ? Can you do Material ID based on sub-UDIM (UV Shells) ?

#8

just move the uvs to the second uv space…
which render engine are you using.?

#9

At present, Mental Ray.

#10

Oglu you left things at a question; do you have more to add ?

#11

what he meant was to give each UV space different color.

0-1 Red
1-2 Green
2-3 Blue

Something like that. Then you move your UV over to that UV space.

If I’m doing this, I’ll probably make a script to select UV island, convert to face and apply surface shader to it. Maybe I’ll paint a texture if the UV isn’t too complicating.

#12

Give the UV Island a different color ?

If one has a UV island, and this particular UV island consists of a coat and a body, because it’s one mesh. You want part of the UV island to have a different color for compositing — unless that is what you are meaning, similar to a material ID based on objects ?

#13

if your body and your cloth is one mesh seperate it…
all that has a unique shader should be one mesh…
face assignment is evil… in most production houses its not used at all…

#14

I’ll proceed with giving a material / UV shell a different color and compositing that method.

Thanks for the clarification :slight_smile: