Bucket artifacts

[Hannes]

I need some quick help. I'm in the middle of a project and get some rendering artifacts I never had. It only appears when I have my cloud layers activated. It seems as if each bucket has a slightly different lighting. I don't use GI here. It's a fill light setup. I already tried detail in camera as well as detail in crop region. Any ideas?
I exaggerated the contrast in this crop to enhance the effect.

[Hannes]

I seem to have solved the problem by myself. I used "conservative acceleration" instead of "optimal" in the cloud's "Optimisation"-tab. Rendertimes are a little bit higher but no artifacts anymore.

[rcallicotte]

Good to know.  Seems like I've heard this before.  Thanks for letting us know the solution.

[Hannes]

Hmm, just made some new test renders, and it looks like there are still some artifacts I didn't notice earlier...
So I repeat my question. Did anybody have similar problems?

[Seth]

I think I did, but looking through my files today, I can't find where...
it is definitely something 1 or 2 years old.
i'll keep lookin for that.
i'll give a shout if i find anything

[Hannes]

Merci beaucoup, Seth. I'd appreciate that.
I could probably reduce these artifacts even more by using "none-highest detail", but this almost quadruples render times!

[TheBadger]

Just following this thread. What does the bucket size do, and how can understanding help me to render better?

[Tangled-Universe]

Just following this thread. What does the bucket size do, and how can understanding help me to render better?

Each bucket represents a render thread. So if you render with 4 threads you'll see 4 buckets being rendered at the same time.
The size of the buckets is primarily determined by the AA setting. The higher the AA the smaller the buckets.

In the render node you can change default bucket size from 256 to 128 for instance, which in many cases offers a little speedup of the render.
This doesn't work for every scene you work on, but that accounts for many more things with TG2

Besides these things I can't quickly think of what else is important to know about the buckets. I just woke up

[TheBadger]

Thanks Martin, on target as always

[Oshyan]

Did you ever find a solution for this? My guess is you would indeed have to turn off all the cloud acceleration, unfortunately. I'm happy to take a look at the file if you can share it privately. You can email it to support AT planetside.co.uk.

- Oshyan

[Hannes]

Thanks Oshyan, I hadn't time to follow this thread, but the only solution was to turn off any acceleration of the clouds. Rendertimes were a lot longer, but the artifacts were gone.

[Oshyan]

Ok, that makes sense. This does become a problem in certain circumstances but in general the cloud acceleration is not too problematic fortunately.

- Oshyan

[Kadri]

I did some test previously. There are obviously render time differences between " Optimization " tab settings.
But...
I did a very basic test now  a crop render on the cloud with " None(highest detail)" was 57 seconds . "Aggressive acceleration " did it in 32 seconds .
Nearly 2 times . The image you render does matter of course .
But after some problems with this  " Acceleration cache " optimization in renders i use always " None(highest detail)" now.
I only change the "Quality" tab settings  for faster renders.

The same crop render with quality  1 (21 samples) with  " None(highest detail)" is 28 seconds. With 0.4 (9 samples) quality  it is 21 seconds.
It is not 2 times faster as you see here.

With a big render and higher quality render settings it may bring significant differences of course .
But i am really not sure if the " Optimization " tab settings brings real render time savings when you have to deal with render problems and have to render the same image many times more then to render in one pass at the " None(highest detail)" settings.