Fireflies and refractive/reflective objects

[redlad]

Hi,

I am just wondering what the general procedure is to get rid of fireflies in scene?

Basically what I have is like a capsule shaped mesh that is a glass material. Inside this I have a disk light pointing upwards, like an 'uplight' effect. But it's giving me fireflies onto the walls and also on the glass itself.

Any suggestions are welcome!

Thanks

[maru]

I would suggest (if you can) to post at least renders, material settings, viewport screenshots. Scene would be best. :)

Usually fireflies are caused either by not enough GI samples, or not enough AA samples, so depending on the cause, you should either increase number of passes (or reduce gi vs aa to have it done in the same time) - to increase overall AA, or increase gi vs aa to have more GI samples.

There is also this guide, which may be helpful:
https://coronarenderer.freshdesk.com/support/solutions/articles/5000501983

[redlad]

Thanks Maru, I am just troubleshooting it now. I find if I turn reflections off on the glass, that it nearly gets rid of the fireflies straight away. But I want reflections on the glass, you know. Trying a few other things like you suggested.

Sorry I can't post the scene or screenshots unfortunately.

Thanks for that link too

[maru]

Sorry I can't post the scene or screenshots unfortunately.

Some maybe something similar, but more simple, where the issue is visible? Is the light inside of a solid glass object?

[redlad]

The light was inside a shape like a capsule, but with the bottom cut away if that makes sense. So it has an opening at the base and it is sitting on another cylindrical type of mesh.

I tried adding a shell modifier to the glass as it is only a single edged poly mesh still not quite right.

[Ludvik Koutny]

Materials with mirror or almost-mirror reflections and small strong light sources will always cause some fireflies in Corona, but only during a few initial passes. Especially if the light source is very close to the surface with this material. It should always converge in reasonable amount of passes though. Meaning it should not be prominent fireflies after about 100-150 passes... just subtle noise. To clear it up little quicker, you can always lower MSI to something like 10, and you can increase GI/AA balance to something like 32 (if it doesn't break sampling balance in the rest of the scene).

[redlad]

I noticed that if I ad glossy reflections, it greatly increases the fireflies, but this could be a mix of noise too. With glossiness set to 1.0, there is no noise and no fireflies.

[Juraj]

Matter of fact stays, these sorts of lights (under glass, any form of lightbulb), are incredibely hard to sample in Corona.. I often fake it for the very same reason (just some self-ilum in there or not even that, and light outside of glass).
But not happy about it.