Screenshots are from Beyond Citadel, developed in UE4. I don’t understand how this is done. Skybox doesn’t affect environment lighting; it looks unshaded, but then you can see that some sides of the pillars are darker than others, and it doesn’t follow any light source orientation logic.
Is this vertex shading, or did the developer apply darker and brighter textures manually on each face of the objects in the environment? Highly unlikely…
It looks like “fake contrast” from DOOM and certain other retro fps games. Eg walls facing east/west are brighter than they’d otherwise be, and walls facing north/south are one level darker.