Removing light influence from Base Color Channel

Hey All,

I am working on a flat toon or non-photo real render setup in 4.27.

My basic materials are set up to use the emissive channel to allow for flat shading. One thing I have noticed though is that base color has it’s own roughness value that I am not sure how to turn off.

Because certain render passes and a few other things we’re working with are set up to function with base color not emissive color it would be very helpful to figure out how to kill the roughness in base color so we can use this channel.

The reason I suspect this channel is Base Color roughness is that Maya has the same setup just with their pre-set up input boxes and sliders. In Maya if you do not set the base color roughness to 0 you will still get light interaction on the surface. I am seeing the same thing here. It may not be but that’s my best assumption.

The standard setup simplified:

Base color - 0
Rough - 1
Metal - 0
Spec - 0
Emissive - custom texture map and intensity at 1

This creates a perfectly flat surface. As soon as you plug a map into the base color you get light interaction with the surface.

For emissive I can control the intensity with a simple multiplied value, the same setup on base color of course controls the color only not the roughness.

Any help appreciated, thank you in advance!

Flat shading basic setup.

For a sanity check I created a fresh level and totally stripped down shaders. Yes I can use a multiply to remove the “base color roughness value” as I am going to call it.

If the base color multiply number is left on 1 it will effect the overall base color value as a note of caution. But if left at 0 - no light influence its shift is minimal.

Note: I should have made a screenshot of this as well, though it may be obvious, but base color with just a 3 constant input looks exactly the same as base color with a multiply 1.