I see this requested here and there and people like to lecture about how it "isn't realistic". Solutions that are offered are too niche for my use-case.
I have a throat texture and need part of it to not be illuminated AT ALL. I cannot base this effect off of geometry because the edge flow doesn't match the texture. I need to fake depth for the throat. I am only using a diffuse map and a normal map:
This looks pretty good tbh but that is because his mouth is at a downward angle. Notice that if I create a new BSDF material with a 100% black color and put it on a cube, the problem is obvious:
How can I prevent light from interacting with part of a texture AT ALL?