issue with passes in exr + denoiser + color correction + glare

[ILS]

I'm having issues with getting the right passes when saving to exr file format.
If i have denoiser enabled with some colour correction and a glare pass but I can't seem to save denoise pass with colour correction but without glare baked in.
I have the save glare channel on and the effect channel checked , I also have save vfb colour correction checked in the exr options.
What I get is cc'd rgb channel, uncc'd denoise channel, cc'd and denoised and glared effects channel and a glare channel that is uncc'd.

This seems to be specific to the exr format, if using tga I get the desired workflow - cc'd denoise without glare and a separate cc'd glare pass.

[Philip Shounev]

Hello,

Could you share some additional details - f.e. do you set the output from V-Ray image file or as a separate channels and respectively, which option do you use for baking color corrections ? It would also be helpful if you could sent the scene for closer investigation to philip.shounev@chaos.com to check out the exact combination of enabled settings.

Best,
Philip

[ILS]

Thanks for getting back to me.
For the exr files I set the path in the v-ray raw image file and the exr file is written as a single file with channels. To bake the color corretion I use the Save VFB color correction to RGB channel checkbox in the file selection window.
For the targa files I set the path in the separate render channels and check the Save VFB color correction to render elements checkbox in the vray render settings dialog.
Here is a link to the max file.
3dsmax 2020 + vray 5.20.23
https://we.tl/t-0G59wFaFk2

[Philip Shounev]

The difference between these two approaches for setting the output is as follows: Baking Color corrections when using separate render channels output will be applied to all render elements, but when setting multichannel EXR through V-Ray raw image file dialog, CCs will be baked only in the RGB channel (and the effects result respectively). So, for achieving the desired results with an EXR format you need to set it through the Separate render channels checkbox.

[ILS]

Thanks
is this considered the intended approach or is there an intention to fix this in the future for the multi-channel exr?
To me this seems inconsistent but maybe there is a reason that this is set up this way.
How will this approach work with the stand alone denoiser tool?

[matanov]

It will be helpful if you share what is the end goal here - what do you want to do with the multichannel output?

[ILS]

I basically want it to follow the same assumption as the tga output.
Denoise channel to have colour correction applied but without the glare effect and a separate glare channel with colour correction applied in a multi-channel exr.
Our compositing workflow is set up for multi-channel exr but the output seems inconsistent with what one expects when using colour correction.

[matanov]

Applying those CCs separately will result in a wrong composition afterwards. The correct way is to apply the corrections on top of the merged elements.

What are you doing with those channels after the render?

How do you plan to use the standalone denoise tool?

[ILS]

oh i see what you're saying.
yes, the cc'd passes won't composite back to beauty once that colour transformation has been baked in.
i guess i assumed that would be obvious when you check the bake cc to rgb channels, and its up to the user to understand that if you want to recomposite from passes to not check the baking option.
my issue is getting a cc'd denoised pass with cc'd glare pass as a separate channel. In this case I don't really care about recompositing because all the colour correction has already been done in vfb.
If i need to do tweaks i have masks that i can use to tweak colours on top of the denoised image.
If i use multi-channel exr i don't get cc'd denoise pass and if i use individual exr files i don't get standalone denoising across multiple frames.
Hope this helps.

[matanov]

So you are doing tweaks based on masks somewhere else? Can't you make those on top of the "effectsresult" channel? Why do you need the glare as a separate pass?

[ILS]

I would like to have control over how much and where to blend the glare pass.
Glare can get a bit intense if you hit an exact reflection angle of a particularly glossy surface, just want to have flexibility to control that in post.