Heavy fireflys in Full LightSelect

[Ihno]

Hi, I have problems in a scene which unfortunately I can't share.
I get a clean rgb beauty but the full light selects contains tons of fireflies.
It seems to only occur when I render it via bb. On my workstation everything looks fine.
But via bb even my workstation has the problem.
Its pretty much standard render settings with animation settings for the Light Cache.
I use a vray camera with an aperture image.



Im on 3.6.04 with 3ds max 2019.

Edit: I sent some of the exrs to the support. The Ticked ID is: 223-156-128 

Tested without luck:
-Adaptive lights vs. Full Light evaluation.
-Dwaa compression vs. zip compression.
-Vray Cam vs. Max Physical Cam.
-Aperture image on/off.

[Morne]

I had similar issues with 3.6 recently. Let me know what support answers you in your email please...

[Ihno]

I will.

Meanwile I continue testing.
Hiding all geometry exept the backplate let the issue disaspear.
Turning on MTL override (grey mtl with low 0,4 glossiness) also worked.

I'm getting closer.

[Ihno]

I tink I got it.
There was a xref scene in which an object accidentally had a scanline standard mtl.
Obviously the light select hates this.

The issue seems to be fixed. Will test a longer sequence without region now.

[Miro]

Any issues with fireflies while rendering the longer sequence?

[Ihno]

Yes, unfortunately I still had issues.
I mailed you a part of the scene which I think I can share.

Afterwards I continued testing.
And I think I finally found the real culprit!
It seems to be the "affect all channels" option in the reflections section of the materials.
It somehow amplifies the reflection and specular on Full LightSelect elements.
This must be a bug.

[Ihno]

Hey I'd like to know if that's a bug that will get fixed of if a fix is impossible for some reason?
I'd love to use that option along with LightSelect.

Also I'm wondering If it could be possible to get a checkbox in matte elements for making only them behave like "affect all channels" is set in every Material.
I think that would be quite useful.

[Vizioen]

Hey I'd like to know if thats a bug that will get fixed of if a fix is impossible for some reason?
I'd love to use that option along with LightSelect.

Also I'm wontering If it could be possible to get a checkbox in matte elements for making only them behave like "affect all channels" is set in every Material.
I think that would be quite usefull.

Second this.

[Fat Tony]

I am having same issue still in latest version.
Some update ?

[vlado]

It's not a bug; V-Ray calculates the lights and the pixels so that the RGB looks good; sometimes individual lights might have fireflies which however do not influence the final pixel value too much when averaged with all other samples in that pixel.

With that said, this will be important to resolve when we implement the Light Mix. For the moment I'm planning a firefly removal pass for the V-Ray denoiser.

Best regards,
Vlado