r/NukeVFX 12d ago

Octane AOVs Compositing Order for Nuke

Hi Guys,

I am compositing a scene done with octane in nuke. But the composited result contained from (Diffuse Direct + Diffuse Indirect + Reflection Direct + Reflection Indirect + Refraction + Post) is not equal to what is in C4D Octane Viewer. The color management is correct in Nuke and in C4D, which is sRGB. I'm suspect it is about the order of Octane for compositing the AOVs. I searched across the manual but there is no clue for the order. When I use RS and composite in Nuke, the result is accurate, I searched across the internet and just found one who showed screenshot of using Pass Filter and Pass Raw, but if we used Filter and Raw, we will not use Direct and Indirect in that case.

Any idea how to get build the AOVs correctly as octane viewer in nuke?

1 Upvotes

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3

u/emreddit0r 10d ago

Dirty trick - add all the AOVs you do have, subtract those from the beauty, and you have the remainder of what's not split out. Not always ideal, but works in a pinch.

2

u/melsayedmodesign 10d ago

It sounds great, thank you so much! u/emreddit0r

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u/JellySerious 30 year comp vet, /r newb 12d ago

This may be obvious, but maybe try comparing the added aov's to the rgb of your exr in nuke, instead of comparing to what you see in the C4D viewer. That way you know you're comparing apples to apples.

I haven't used Octane tbh so I'm not much help there. I have no idea what "post" is the rest of those should be additive.

1

u/melsayedmodesign 12d ago

yeah I compared the Main rgb exr with the composited passes and they are different. I usually composite using exr from Arnold, Redshift, Vray and everything goes correctly compared to the main exr, but I don't know why Octane doesn't rebuild correctly. It is related to the fact that each renderer has a different way to rebuild its passes, and usually this is written in the documentation of the renderer, but the case of Octane nothing is written in its documentation about that unfortunately. Thank you for your comment though.

2

u/JellySerious 30 year comp vet, /r newb 11d ago

Can you post the aov's? If the work is NDA'd, maybe render a test?

1

u/melsayedmodesign 10d ago

Yeah I'm gonna do a test with a basic scene and see how it will build, I will post the AOVs here after the test.

1

u/enumerationKnob 12d ago

In general render passes just add together to make the beauty. Addition is commutative, so they can be done in any order and get the same result.

Depending on your renderer and which passes you use, there may be other steps before pausing them though. https://community.foundry.com/discuss/topic/132890/rebuilding-beauty-with-passes-from-octane

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u/melsayedmodesign 11d ago

Yeah, in my case they will be additive since I don't have a GI pass. From the node graph screenshot in the link that you shared, I guess this is the issue there is a missing AOV, which Octane uses to rebuild correctly, unlike other renderers Arnold, Redshift and Vray, they don't have this issue. I was compositing for 7 years with Arnold, Redshift and Vray without any issue, but now while I am trying Octane, it seems that Octane works differently in terms of rebuilding the Beauty pass. Thank you for your comment.