I'm having a look at IIF config.ocio and I was wondering how you build the aceslg2_to_Rec709.cube LUT for the rrt_odt_r709 colorspace.

I'm asking because when I compare an OCIOColorspace node (in : aces, out : rrt_odt_r709) and two TuttleCTL nodes (one with the RRT 2.2.1 and another with the REC701 softproof ODT), there are some differences :

- a small shift

- + some noise in yellows with OCIOColorspace node.

Here's a screenshot of my nuke scene and a jpg export with TuttleCTL nodes and an OpenColorIO Node.

For my tests, I'm using an XRite colorchart shot with a Red One and exported in EXR thanks to REDCineX (ACES option enabled).

am I mis-using the OCIOColorspace node ?

Anyway, I will be pleased to understand how the LUT was processed and configured in the ocio config file.

I don't fully understand the purpose of the AllocationTransform vars before the FileTransform :

Thanks a lot !

Marie