Movable light affects SSAO differently depending on shadow on/off?

I’m having some trouble with movable lights, they fail to cancel out ambient occlusion if they aren’t casting shadows.

Shadow on:

Shadow off:

Anyone know why this is, or have an idea how to fix it?

SSAO is calculated in shadowed areas, so since that point light is not casting shadows and another light below is, you’ll have AO in that area. If you find a solution for that please share, but as I know it works like that.

SSAO is calculated to fullscreen always. At SSAO pass there is not any information about lights or shadows. But in physical based HDR lighting direct portion of light usually wash out all indirect light details like ambient occlusion.

I guess you are seeing feature that makes non shadowed lights to use SSAO as aproximation of shadows.

Yes, it’s calculated fullscreen, but what I meant is that shadowed lights have always washed at least 75% of AO in all my projects. If you use AO Buffervisualization you’ll see your SSAO pass on all the screen and assets in the scene, but you won’t see it at all in areas which are lightened by shadowing lights. That’s why he sees AO turning shadows off.