Changing materials within a slab

[Anonymous]

Greetings,

I have modeled slabs for the ceiling/roof components of a mixed use project and I wanted to show a wood material on the underside of the slab only. When I change the underside of the slab to a different material than it was modeled with, I don't see a change. When I tried changing the sides of the slab to a different material, all the surfaces change to that material.

Anyone know how to fix this?

URGENT!! PROJECT DUE TOMORROW!! ANY HELP IS GREATLY APPRECIATED!

Thank you in advance.

[Eduardo Rolon]

If you are using AC17 you need to override the Material by clicking the button. For 16 or earlier you just select it.