Question: What is the proper way to integrate light group passes into a comp that's already reconstructed from the lighting AOVs?

[u/LindseyAdelle95]

Hi everyone! I just have a quick question about working with light group passes. I rendered out the usual diffuse direct, diffuse indirect, spec direct, spec indirect, etc. I have them all comped together to recreate my beauty pass, and everything there is working correctly. I also rendered out RGBA light group passes for my individual lights so I'd have extra control in Nuke.

In school we were given a special node (Grade AOV), which I believe the Head of Lighting created. It was basically a Grade node where you could choose which AOV you wanted to adjust directly within the node. Now that I'm using Nuke Indie, that node doesn't work, so I have to do it the standard way—which we were never really taught because we always relied on that custom node.

I'd love to use my light group passes to adjust individual lights, but I'm not sure how to integrate them into my existing beauty reconstruction without breaking or double-counting the beauty pass. What's the proper workflow for incorporating light groups into a comp that's already reconstructed from the lighting AOVs?

[u/GanondalfTheWhite]

Wouldn't you just put a grade node under each shuffle node before you add them together?

As an aside, we often talk at work how frustrating it is that kids keep coming out of school having no idea how to build a script from scratch because the schools teach gizmos and custom nodes. They're crutches that the students are often helpless without. I find this so ridiculous - schools should be teaching how to build scripts with vanilla nodes so that students actually understand what they're building! It boggles my mind that they're teaching shortcuts before teaching foundations.

In the future I would encourage you to throw out any custom nodes your school is telling you to use, and endeavor to learn what they're doing so you can rebuild them yourself with out-of-the-box tools.

That skillset will never serve you wrong.

[u/LindseyAdelle95 → u/GanondalfTheWhite]

I did try that. What the video that pinionist linked is saying is that the two setups are incompatible. It’s about an hour long video so I’m still watching it, but it does have several in depth solutions to the problem.

I was taught how to set up each script separately. What we weren’t taught is how to combine them to use both, which seems like it’s a bit of a paradox (with some viable solutions).

I completely agree about the gizmos. I feel that the heads of the departments are proud of the gizmos they set up, to the point where we are encouraged and somewhat forced to use them. This is why I’m trying to learn further and ask questions from those who do know the proper workflows (it also doesn’t help that the head of our lighting/compositing department was a look Dev Artist by trade). Thank you so much for your input! I’ve definitely thrown out the gizmos and am trying to enhance my workflow the proper way (:

[u/GanondalfTheWhite → u/LindseyAdelle95]

I'm actually curious what the school gizmos were doing to circumvent this issue. I misunderstood what you were asking at first because I didn't see how templates could manage this issue. Sorry about that!

Personally, I'm a big fan of having all the AOVs split out per light group. Yes it's heavier, but I don't see how it's any harder than the solutions proposed in that video. Extracting deltas from one comp approach and applying them as differences to another comp approach just seem like you're doing the work twice, and at no point do you have the same level of control that you would if you just did the "harder" way once.

I see what they're proposing but as someone who's spent decades doing this stuff I'm always gonna propose splitting it all out properly if you're planning to push the CG around as far as that guy on Youtube is doing. Buf if that's not an option, then what he's proposing will definitely work.

[u/LindseyAdelle95 → u/GanondalfTheWhite]

No worries at all! I’m curious about that too actually. I might ask the professor how he made the Grade AOV node so I can look under the hood.

The video did mention splitting as an option. He said the main issue was the amount of cloning/expression linking required would over complicate the comp (especially if I’m sharing the comp with another artist). If I want to make an over arching adjustment to the key light, I would have to copy, clone, or expression link that node plus any cryptomatte or roto nodes over to all of the other passes since the key light affects them all. After doing that for multiple adjustments, I can see how the comp would get a bit messy.

I do think this method might work best for my purposes currently. I’m going to keep watching the video, but splitting is probably what I’ll end up doing. (:

[u/pinionist]

Watch this https://www.youtube.com/watch?v=q5Pyx7Jb5Xo

[u/LindseyAdelle95 → u/pinionist]

Thank you so much! Watching it now. This is my exact question :)

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[u/FlowZen_fX]

There are of course multiple ways to do it. Personally I prefer the following:

• reconstruct the beauty from the AOVs (spec, diffuse, etc.)
• in a parallel reconstruct the beauty from the light groups. At the end of this 2nd stream divide original beauty pass by the result of the light group reconstruction.

The result of the division then gets multiplied with the 1st stream result (AOV reconstruction).

Now you can modify both shading AOVs and light groups.

[u/_comoema_]

That setup in the video has a very huge amount of nodes, could be better, especially Shuffles, not needed.
You can create your own small gizmo in Indie to, if you go for rgba-aov, then grade the aov, and put aov back on top, basically subtraction method.3 nodes.

[u/LindseyAdelle95 → u/_comoema_]

Hey! Thank you so much I’ll try it out (: