OpenColorIO TOP issues

I’ve noticed quite the bunchful issues related to OpenColorIO TOP so here’s a quick recap of what should be some fairly easy fixes to bring to the table.

With the Build 2023.11760 of May 03, 2024 we’ve seen an update in the OpenColorIO SDK to version 2.3.2 from (I haven’t been able to track what the older version was) which gave us a lot more options than before (41 color spaces vs 14 of them).

First issue, there is no way to know which of these 41 color spaces are the old sRGB and Linear spaces as there are way to many of them who have sRGB and Linear in their names, making it so that the only way to know for a fact that you’re doing the classic correction is to spawn a Math TOP and turn on the “Convert Incoming sRGB to Linear” parameter.

At first I thought I could just open an older TD network created before the update thinking that it would show me which sRGB and Linear are the correct ones which is when I noticed that doing so will make it so that the Ocio node created in the older version will still use the older color spaces whilst the new one (rightfully) doesn’t.

If you wanna replicate this scenario, you don’t even need to install an older version of TD because, going to the Operator Snippets for the Ocio node will actually still use the older version of the node, with the (correspondingly) old version of the color spaces.

TD version 2023.12120

O.S.: Microsoft Windows 10 Pro
Version 10.0.19045 Build 19045

Hardware:

CPU: AMD Ryzen 7 5800X 8-Core Processor

RAM: 32 Gb (4x8GB) Crucial Ballistix 3200 MHz RGB

GPU: NVidia GeForce RTX 3070 Ti ZOTAC Gaming AMP Holo

Also, if anyone know which colorspaces of the updated version corresponds to the old sRGB and Linear I’d be very grateful to you.

That’s absolutely up to the configuration you are using, in theory, you could just load the config that you were using before in this new build and the same choices should appear.

Otherwise, it’s wise to read up on the provided configurations to understand what workflows they are actually trackling. For instance, recent OCIO versions bundle ACES-centric configurations for CG and film workflows, they use a special URI instead of loading a file (OCIO CG Config for ACES).

At first I was thinking of finding out what version of the SDK was previously being used before the update and track down what the equivalent would be for the newer one.

I think I’m gonna stick with the simplemost version of it which seems to be to use the Math TOP and toggle on the sRGB to linear option which perfectly corresponds to the old version of the OCIO SDK (like mentioned in the post).

This obviously only makes sense because I’m not using the OCIO TOP to its full potential but only as a color correction tool for colored pointclouds when imported in TD since most softwares (mainly Blender in my case) outputs them in sRGB by default and I always forget to set it to linear instead.

Thanks for answering and let’s see if Derivative says anything about the other stuff.

OCIO is more of a framework than a library. All the important definitions are part of the config file you have loaded (Setup page). It’s likely you were using the ‘nuke-default’ config before and now it’s something else, hence you see a bunch of different source and target space conversions. There’s not much to say besides ‘load the config file you were using before’ or ‘read more about digital color spaces and OCIO’ so you can pick the right one for your workflow.

@Papacci20 Sorry about this, it threw me off as well a few montths ago and I had to ask. We have a note to update the documentation to help point to the old setup, but its stuck in backlog. We’ll raise the priority!
To load the pre-SDK-update opencolorio configuration file, load /nuke-default/config.ocio on the Setup page.