[Solved] Selective Ambient Occlusion

Hi everyone,
is there a way to enable ambient occlusion (AO) only for some render layers? I need different lighting conditions to emulate moon surface as seen via a room window, so that inside the room (with atmosphere) there is AO, but outside there isn’t.

In Cycles, you can have even more flexibility in that. You can use the AO shader node to tweak the effect on a per-material basis or even by way of a mask.

Thank you, I use Cycles, can you please explain more how to make a mask? Per material basis seems too complex for me and makes materials less reusable.

Masks can be made by use of many different node types, the texture nodes, the layer weight node, the attribute node (for Vertex color data) ect… Basically anything that can can output in black and white colors.

You can also reuse setups by way of the creation of group nodes, you can create an ‘add AO shading’ group node (with adjustable value fields) that you string all your materials through before plugging it into the output.

Thank you very much. It helped a lot. I found that I need to apply AO node only to some diffuse materials to make scene appear enough realistic (at least as I see it).