Question like in topic. I want mark(color or somehow) different areas(faces) of mesh not via face material, but somehow else.
Why?
Because in many applications(game dev/etc) new material is like different object and it split mesh into parts.
also texturing i would prefer only for one material
So in short, i want to maintain my current material colors(somehow) to see if topology is still correct, but have only one material for all model.(as one mesh)
That depends on the specifics of the game engine you are dealing with. Would it work to bake the combined materials into a single new material?
one way would be to make a copy and bake all mat for export
that way can always come back to your original model
happy bl
i need blender material Node system - cycle render for principled BSDF shader. thats why i also need one material only, but still want see faces in different color(only in blender) to see topology
so i understand bake is not solution here as it will just bake texture.
no other solutions?
Vertex colors could be used directly or as a mask for a texture(s).
Edit Mode.
Select faces that are to be colored.
Vertex Paint Mode.
Do Shift K (Flood Fill) of the color.
yes, i thought about it and tried, but problem is it mark only vertex, not all face. I mean if you have red face near blue face, what will you color vertex that is between them? it dont look correct ;/
Select whole faces only (use face mode) and follow the listed instructions.
Result:
Old script for this if you want a speed boost:
I have a better / less dangerous version somewhere
oh, didnt knew about it, thought vertex color, is all vertex, so cant partially, thanks 
thats the solution
also one question more if possible. probably easy one.
how can i see vertex paint, without entering vertex color edtior? is this possible to see this colors in edit mode?
You’d need a node tree. This is an example from Cycles.
I think Blender Render can access the Vertex Colors similarly.
ok got it, will just switch materials between standard one and other that show vertex colors, it sounds nice.
Thanks again!
two materials with F to switch, one will be preview with setup like you show on screenshot
