Greg Hughes

I have a reason for using the AO map. It is often used in game engines. In Maya, for example, you can directly feed it in to the material.

How do I use an Ambient Occlusion map with the Principled Shader? There are fields to use PBR maps for Base Color, Normal map, etc, but I don't see one for AO. Or is there a way to multiply the AO map with he Base Color map? If so, how?

I have tried using a Layer Mix node but this blends the maps making the Base Color map less saturated, so it is not the way.

I am using a Principled Shader. In the Textures tab for Source Color Space there are only two options: Automatic and Linear. The Automatic option does not correct the image (it appears over-saturated an dark), while the Linear option is closer (not as saturated) but it is too light.

How would I use the ocio colorspace transform node?

Edit: I think I found a way to do this with the OCIO Transform node inside a VOP COP2 Filter:

https://paperkrane.io/articles/converting-image-textures-hdris-to-aces-in-houdini/ [paperkrane.io]

I found that I also had to uncheck Linearize Non-Linear Images in the File node since I used an SRGB texture map. The To Space: ACES - ACEScg gave closest result.

However the result is still darker and more saturated, so I added a Color Correction node to the Material and increased Gamma to lighten it.