Occlusion in diffuse
polycounter lvl 8
What is meant by that Albedo must be pure color and must not contain any occlusion as was the case with diffuse maps ? I've read on how PBR works and so forth, as someone who was accustomed to painting diffuse maps, I never included any occlusion, for example; I assume, occlusion painted in a diffuse for a human eye, is what is referred to as occlusion ?
Replies
AO should only mask ambient lighting, not direct lighting.
For example if you put AO into the albedo texture for your characters mouth, then what happens when you shine a flashlight in there? It's just black. Not great.
Albedo as pure color allows the lighting to be more realistic.
Sometimes the names of things can make shit confusing as hell, but in this case, the function is defined precisely in the name.
Ambient (referring to games lighting) = An ambient light source represents an omni-directional, fixed-intensity and fixed-color light source that affects all objects in the scene equally. (from wikipedia)
Occlude = stop, close up, or obstruct.
So ambient occlusion is saying how much of the ambient light you are going to block. Since video games can't compute lighting with the complexities of real life factors, you have to use simplifications like this to achieve a more realistic look. Ambient lighting is the simplification, and ambient occlusion mapping fills in *some of* the unrealistic gaps ambient lighting creates. You bend your elbow, in real life not all of the light bouncing around the room is going to get into that crease, so it's a little darker, right? Video games don't yet have that full simulation, so we use ambient occlusion map to just fake it in places we know should be a little darker. And obviously, as mentioned, a direct light source overules the ambient occlusion, as you'd expect.
It's not the most realistic way, but you can't always afford it, or want it.
Anyone who's a "big time master" should know this haha. Sorry, your nick in caps always cracks me up.
I think most PBR renderers use IBL for ambient, whether a single cubemap (Marmoset) or else a bunch of tiny cubemaps as "light probes" to get a kind of localized bounce lighting across your whole game level.
All these "soft" indirect lighting sources should be occluded in recessed parts of the model. Down in between the couch cushions, etc.
But the occlusion map shouldn't affect any "direct" lights. The sun, a streetlamp, the flashlight, etc.
When you're talking about eyes, I think occlusion is when the retina gets cloudy or milky, through disease or injury. Not the same kind of occlusion we refer to in games.
A creative sheep, harhar, wotsit. Poopipe, poopinmymouth, now THOSE are proper nicks. Always go for the poop jokes.
I believe I understand, it was the quote I read regarding occlusion in diffuse which I thought, I never used occlusion in my diffuse maps !
I've used this screen name since I was a teenager playing xbox live. Sometimes I wonder if I should update to something more professional, but, as mentioned, there is guys calling themselves "poopinmymouth" (which I can't even type without cracking up) so, I'm probably good.