If you have vertex color on your highpoly model, and you want to bake it to a diffuse map, you can make a material for the HP with a Vertex Color Map in the diffuse channel, and this will then bake into your Diffuse element in RTT.
Face id's work in conjunction with a multi/sub material, so if you've already set your ID's, just throw a multi/sub mat with a different diffuse color per mat. You don't need textures. If you've made vertex color, do what Eric said. Id/multisub is easier to edit/maintain tho. Then bake as diffuse.
Hello guys, thats my situation. I created a Hp Model in 3ds max and reduced it on a low poly. I done an unwrap for my lp and baked a normal and an ao map out. all this worked fine and the maps looked good. I got many single details like bolts on my hp model, which are deleted at the lp version to get a lower polycount. I…