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I really hope I'm doing something wrong: the ambient occlusion, in my knowledge, should be a calculation that's more related to geometry and light direction and directional shadows. I'm attaching two images of the same scene.

This is what a typical AO pass, calculated with other 3D applications, looks like:

enter image description here

This is what Cycles generates when AO pass is activated:

enter image description here

First problem, I can't consider the latter an AO pass, that's something else. Actually, I noticed that this happens for interior renderings. For geometry that's not enclosed, the AO looks just fine.

Second: although I activated the de-noising for this rendering, the AO pass remains unaffected.

I'm not listing any specific settings I used, since this happens with just the default Cycles' setting and the AO pass checked. Right now I just need to clear out this doubt: have I missed some parameters or is Cycles just doing AO wrong, for interior scenes?

Thanks!

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  • $\begingroup$ Hello and welcome. You might need to check and share your settings, because that second image does not look like an ambient occlusion pass, looks more like a beauty pass with ambient occlusion $\endgroup$
    – Emir
    Commented May 29, 2023 at 11:06
  • $\begingroup$ Hi Emir, I agree it desn't look like an AO, that's the point of my whole question, but that's what Blender compositor visualizes when I directly connect AO from the "Render layers" node, to an Output node. I definitely fear that's what Cycles considers AO. I'll post more information if needed, but let's see if someone is already aware of this as an issue. Thanks! $\endgroup$
    – Etord
    Commented May 29, 2023 at 12:04
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    $\begingroup$ "This is what a typical AO pass, calculated with other 3D applications, looks like" This is not real ambient occlusion, that looks like SSAO, Screen-Space Ambient Occlusion, which is an approximation for real time rendering. Cycles doesn't produce this because it is a raytracer, at least not without some non-trivial node trickery. The second image is probably a lot close to real AO even though it is not what you want $\endgroup$
    – Duarte Farrajota Ramos ♦
    Commented May 29, 2023 at 12:13
  • $\begingroup$ Yes exactly, that's more like a dirt shader applied globally, and that's what I was looking for from Cycles. I believe it's possible doing that by adding an AO node to each shader in the scene, but I don't think that's reasonable. So, if there's no practical way to obtain a SSAO or global "dirt" pass with Cycles, that dashes my hopes. Thanks anyway! $\endgroup$
    – Etord
    Commented May 29, 2023 at 12:38
  • $\begingroup$ You should really check your settings. This is the AO Pass from one of my Blender renders imgur.com/a/rc6BuEA and i did not add AO node to them. If thats what you are looking for, then something is not right with your AO Settings $\endgroup$
    – Emir
    Commented May 29, 2023 at 19:16

1 Answer 1

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For future Reference.

You can change AO distance inside Fast GI Aproximation. Render Settings > Light Path > Fast GI Aproximation > AO Distance

enter image description here

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