Reflection/Firefly Issue

[hartherb_jj]

Hello,

it has been some years since we last had fireflies in one of our renderings, but since a few weeks we occasionally get them.

We tried to nail down the problem and it seems it´s due to our ReflectionMap. We use a simple plane with an VrayLightMtl assigned. The VrayLightMtl has an image in the lightcolor slot and an alpha map in the opacity slot.
I´ve attached a simplified version of our setup with a checker map in the opacity slot.
If we disable the opacity map everything renders as expected, but with an opacity map assigned we get fireflies.

Any idea on how we can get rid of the fireflies and still use the opacity map?

Thanks and br,

[matanov]

Hello,

I don't get fireflies with the attached scene. Also there is no map in the lightmtl color slot.

[hartherb_jj]

Thanks for your reply!
That´s interesting, here is our Rendering:
We use Vray Next update 1.1, but I will install update 2 and see if that helps.

[RichardBlank]

I’ve also had firefly problems lately. Updated to 4.2 and it got worse.
Im going to send a scene to the support and see if they can find out what’s going on.

[piotrus3333]

isn’t that one of the issues that appeared after implementing Adaptive DomeLight? is there a dome in the scene?

[vlado]

Similar to Peter, I can't reproduce the fireflies with the latest builds on our website (although they are present in the 1.1 update, and no, they are not caused by the adaptive dome light).

If anyone else has issues though, it would be great to provide a scene or some other way to reproduce it.

Best regards,
Vlado

[RichardBlank]

I'll upload a scene for you asap!

Here's a .mov of the issue.
https://we.tl/t-8sk08bI6Dz

[RichardBlank]

Here's the scene. Warning! It's a big one...

https://we.tl/t-vFfqxNBu3f

[matanov]

Here's the scene. Warning! It's a big one...

https://we.tl/t-vFfqxNBu3f

A Falloff map assigned in the Refl. Glossiness is the problem here. I've logged the issue, thanks for the scene!

[RichardBlank]

Ok that's good to know! So if I remove the falloffs, will the fireflies go away?

[matanov]

I believe so. Look for them in the FP autocreated materials.

[RichardBlank]

Yes I changed the value to around 0.8 in the second slot and now it renders fine. Thanks!