Ambient Occlusion?

Seven193Seven193 Posts: 1,080
Where would an ambient occlusion map go for a Iray Uber surface (PBR Metallicity/Roughness) ?

Albedo -> Base Color
Ambient Occlusion (AO) -> ???
Height -> Base Bump
Normal -> Normal Map
Roughness -> Glossy Roughness

Post edited by Seven193 on

Comments

  • JonnyRayJonnyRay Posts: 1,744

    It doesn't. Ambient Occlusion is used by biased renders (like 3Delight and other Renderman based engines) to fake how light bounces in surfaces that are close to each other. Since Iray starts from a psuedo realistic light model, the AO map isn't needed. The way light bounces in the scene will already take care of that effect.

  • Seven193Seven193 Posts: 1,080
    So, if Ambient Occlusion is a type of fake lighting, it would be wrong to try to blend it into the diffuse map using Photoshop? Thanks.
  • Sven DullahSven Dullah Posts: 7,621
    Dave230 said:
    So, if Ambient Occlusion is a type of fake lighting, it would be wrong to try to blend it into the diffuse map using Photoshop? Thanks.

     Yes that's correct. You would double the amount of AO if using Iray or other PBR engines.

  • An AO map can, however, be used to mask wear or dirt (light areas are more exposed, so might be worn/plished - dark areas are in nooks and crannies, so may have accumulated more dirt). You could perhaps use the AO map, inverted, in Top Coat to add a layer of dirt as a grunge effect.

  • JonnyRayJonnyRay Posts: 1,744

    That's similar to how Stefan (Stonemason) talked about using the AO map when he was planning for the dirt and wear and tear of his textures. It could be used to mask dirt or to lighten areas that might have rubbed off some layers of paint.

  • May well be where I picked it up from.

  • NukeBunnyNukeBunny Posts: 1

    Very late to the post, but found that AO maps work nicely if you check 'show hidden' on your surfaces tab and drop them into the diffuse strength.  They also work well in gloss strength or color if no other maps are used to give a bit more contrast to specular highlights.

  • Richard HaseltineRichard Haseltine Posts: 100,948

    Generally if a property is hidden it is because it is not relevant to the current settings, so I am alittle suprised that they do anything.

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