Yeah, I always was perplexed by that tendency in Doom3… I mean, I get that lighting calculations aren’t tracing the effects of light past the first surface it hits, but does it have to be black when there’s no lights hitting a surface? Couldn’t they have done a cheap approximation of “ambient light” based on how many lights there are nearby, and use that light level as a minimum for totally occluded surfaces?

I remember reading that the choice to use black was literally a performance optimization because the renderer got to fully skip drawing surfaces that were fully occluded and it saved some render time. Then I also read that it was a design choice to give it a more panicked environment because you couldn’t see what’s in the shadows… but it always looked clunky to me, seeing fully black areas when there’s clearly a lot of reflective scattering surfaces around.