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Cycles: move sss and diffuse transmission into diffuse pass
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Authored by Brecht Van Lommel (brecht) on Feb 14 2020, 1:04 PM.

Details

Summary

This simplifies compositors setups and will be consistent with Eevee render
passes from D6331. There's a continuum between these passes and it's not clear
there is much advantage to having them available separately.

Diff Detail

Repository
rB Blender
Branch
transmission (branched from master)
Build Status
Buildable 6617
Build 6617: arc lint + arc unit

Event Timeline

Code-wise LGTM. Seems to work as expected tested viewport, final render cpu, gpu and OSL.

This revision is now accepted and ready to land.Feb 14 2020, 4:18 PM
Yegor (Yegor) added a subscriber: Yegor (Yegor).EditedMay 2 2020, 8:12 PM

This is clearly a not very good decision regarding compositing. We cannot drive translucence and sss separately anymore.
The picture is from 2.82.
Is there a better solution for the eevee passes consistency? Because this one kills compositing quite much.
To make it clear, sss pass lets you increase or decrease sss factor on compositing, as well as the color of sss. Compositing is not about simplification. It's about giving all the possible information to a compositing artist. What we need is not reducing the number of passes, but in contrary add more as much as possible.

there is much advantage to having them available separately.

For sure, keeping passes in diffuse is faster, but not flexible enough to satisfy the full range of production needs.

When we add light path expressions there will be precise control over this, but I don't plan to change the current behavior. These changes are unrelated to performance.

When we add light path expressions there will be precise control over this, but I don't plan to change the current behavior. These changes are unrelated to performance.

Yes, they are not faster in perfomace way, they are faster in production way as they simplifies compositor setups.
It is nice to know that precise control is planned, it is definitely simplicity vs flexibility issue.
Thank you for the answer.