[bug] global volume render, lots of fireflies 1.2.1

[elindell]

Was trying to render out a scene with concert like beam and wash lighting and I noticed that it produced a terrible amount of fireflies, much more than I've noticed before when using corona. I made a simple scene to test with a disk area light and a simple single bounce volume material for the global volume. I used 1.2.1, then re-installed 1.1.1.

1.1.1 version comes out much cleaner, take a look.  I only did about a minute render for the renders below, but the 1.2.1 just gets more and more fireflies as time goes on when I tried to let it clean up, its unusable.

1.2.1 version


1.1.1 version


thanks

[maru]

Unfortunately there is a "problem" with disc light in newer versions. You can take one of these workarounds:

1. Go to performance > devel/experimental and change lights>solver to any other than "better object-based"
2. Create a flat disc object and assign Corona light mtl to it

[Ludvik Koutny]

I would first make sure disc light is a cause here. There may be some other bug too :) Any chance you could provide us with a scene?

[maru]

Psst, Rawa, the scene is in 1st post. ;)

select "single bounce only" in volume mtl to make everything render faster,

disk = fireflies
disk + emit on both sides = ok

rectangle = fireflies
rectangle + emit on both sides = ok

sphere = ok

cylinder = ok

switch lights>solver to other than "better object-based" = always ok (even disk and rectangle)
(or sampling mode to "lights only" but this will make things crazy in some cases)

Corona light mtl seems to be less noisy than lights.

Also, this:
(viewing angle)

[elindell]

thanks for taking a look all, changing the light solver was a quick fix that worked, I guess I will use geometry for light in the future until this is fixed

[Ondra]

I found the cause and moved it to our internal bug tracker, I am hoping to fix it soon