Do you use AO maps in yours PBR materials?

kurt_hectic

Hello,

I'm asking this question because basically I couldn't found a difference between material with and without an AO map.
I hook up a pure black color and still nothing. Then I start to search why, info. from 2014 but probably still valid:

https://answers.unrealengine.com/questions/9750/is-there-any-benefit-to-an-ao-material-input.html
https://answers.unrealengine.com/questions/101059/ambient-occlusion-node-in-material-does-nothing.html
tl;dr AO map works only with indirect lighting; So when we have a direct light in our scene there won't by any benefit from it

So I'm asking a question: how I should set up a good looking PBR materials for stuff like terrain? With sun position around noon, when normal map will be barely visible, without AO there will be almost pure albedo....which is super flat and ...damn, it look just bad. It not supposed to seen separeted, without other maps/layers which create one thing.

Any info. advice?  How do you set up AO in your engines/games?

Cheers,
k

Obscura

Ambient light can be caused by skylight as well. So lets say you have a directional light and a skylight, the non lit side of the mesh would get some brightening to its shadows from the skylight, and it "counts" as ambient light. So you should see your ao map showing up there. Normal maps are also taken into account, so back facing angles, compared to the light direction should also show your ao map.

Obscura

JordanN

When UE4 first launched, I used AO maps for every object. In real time lighting, the difference was always apparent.
Over time though, Epic did include new updates that could calculate ambient occlusion entirely, making the AO map feel redundant. I also never used them for props baked in light mass (since they were static).

Obscura

"Epic did include new updates that could calculate ambient occlusion entirely"

Not really sure about what do you mean by this.

JordanN

Obscura said:

"Epic did include new updates that could calculate ambient occlusion entirely"

Not really sure about what do you mean by this.

I'm on my phone right now but you can find distance field AO on their site. There is also Voxel GI (but that requires a ton of GPU power). I never saw the need for AO maps after that provided you want to build a game with those specs.

For games built with Xbox one or mobile phones in mind then it's out of the question.

Obscura

Distance field ao is really low resolution, and it uses mesh distance field. Its quality is nowhere close to a per pixel one. But for medium scale ao only from meshes and not normal map details and stuff, its fine. But you would usually want a combination of these. Because any detail that only exists in the normal, distance field ao would not take into account.

leleuxart

AO in the material occlusion slot for the very small information, SSAO for medium, DFAO(if you can afford it for the project) for large-scale AO. Lightmass AO can be combined with SSAO if you're baking for the medium to large scale [static] AO. DFAO can also be applied based on the occlusion map baked from the Skylight.

kurt_hectic

OK, thanks for the info. I'll add a skylight and check how it affects my assets.