ACEScg Comp/3d render sanity check

Hello everybody,

I’m setting up an ACES pipeline that also involves a lot of 3D rendering in Houdini.
The grading facility supplied us with ACES 2065-1 EXR plates.
I’ve setup an OCIO config with some CDL’s and the standard ACES ODT’s, etc.
We preview our work using the default ACES/sRGB odt.
All good, we did a roundtrip through Nuke back to the facility. Everything fine.

When we get to the 3d part, we load in the EXR plates in Houdini.
Now, obviously all the textures and HDRI’s are converted to ACEScg. So rendering happens in ACEScg land.
When I bring in a EXR plate, am I supposed to convert this to ACEScg too?
If I do this inside Nuke or Houdini, the colors change slightly because of the different primaries.

However, when I do that and view through the ACES/sRGB output, the colors no longer match with what we see in Nuke.

So what is the workflow here?

Scenario 1.
Should I create a extra ODT which converts from ACEScg --> ACES 2065-1 --> sRGB? So we see the same as we do in Nuke again?
That way we work in full ACEScg land in Houdini and we have a visual match with Nuke.
When we import our renders in Nuke we interpret as ACEScg and we see the same again.

Scenario 2.
Or, should I leave the plate in Houdini “as-is”. So ACES 2065-1.
Then I see the same using the same ACES/sRGB odt we use in Nuke.
However, then we should adjust our lights slightly becuase of the different primaries, which feels counterproductive.

Could somebody enlighten me?


David van Heeswijk
Freelance VFX Supervisor - TD