Why are there lines in the atmosphere?

[dmobile1337]

that would be so unbelievably awesome!

[dmobile1337]

Well, I just got the patch and am doing a test render now.  will let you know what happens.

[Oshyan]

Please don't PM or email other users with links to the Deep edition installer. Registered users should be on our mailing list for notifications of updates. If they are not it is an issue we have to deal with internally, otherwise they will continue to not receive updates, and this is a situation we obviously want to remedy. Additionally their registration information must be verified before they can receive the update.

dmobile, did you happen to reduce Sample Jitter in the Atmosphere Quality tab? If not can you provide a .tgd for reproducing this issue?

- Oshyan

[dmobile1337]

Yes, Sample Jitter is reduced to zero for atmospheric quality and for the quality if the cumulus clouds themselves.  I am doing a test render with the new version, if the problem persists I will supply a .tgd file.

[Oshyan]

The reduction of Sample Jitter is the source of your problem. Although it can in some ways reduce noise for a given sample level, it also almost invariably introduces these bands, except in very clear atmospheres. It is recommended that you not reduce sample jitter, particularly for the atmosphere. A value of 1 is ideal in most cases, and in fact larger values can help avoid atmospheric banding that occurs in certain other specific situations.

- Oshyan

[dhavalmistry]

sorry Oshyan....just so you know...I didnt PM dmobile1337 with the links....

[dmobile1337]

Thank you!  But I wonder now, I was using a value of zero for sample jitter because it removed the grainyness that was appearing in the atmosphere.  Is there a better way of accomplishing this goal?

[sonshine777]

Thank you!  But I wonder now, I was using a value of zero for sample jitter because it removed the grainyness that was appearing in the atmosphere.  Is there a better way of accomplishing this goal?

Raise the atmosphere Quality (default is 16) try 64 to 90

[dmobile1337]

I tried that but it added to render times.  Sample Jitter reduced  to zero provided the same effect and saved render time. 

[sonshine777]

That is one trade off. Sometimes it is just a matter of playing with the numbers. You may want to try to lower the render quality by .5 and up the atmosphere quality, it may help the render time.

[Matt]

Unfortunately there's no way around this. If you reduce sample jitter you remove noise but introduce banding artefacts. There is no substitute for increasing the number of samples unfortunately.

Matt

[dmobile1337]

Well, software like this makes the time worth it.  This just made sense as a workaround and only recently started appearing.  Is there a point at which samples in the atmosphere stop having an affect?

[Oshyan]

The need for higher atmosphere sample numbers depends on the specifics of the scene. Essentially greater numbers of samples have diminishing returns as you approach a "noiseless" render (as far as the atmosphere is concerned). The ideal is 0 artificial (due to undersampling) noise. For normal daylight scenes values of 16-32 are usually fine. You may need 64 or higher for heavily shadowed scenes. Whenever there are strong atmospheric rays present, or the sun is visible through a cloud, the need for samples to ensure a noiseless result increases. I would never use more than 256 samples, even in extreme cases, although even that level will sometimes not produce a noiseless result. We hope to be able to improve these difficult situations so that they do not require such extreme render time for appropriate quality.

- Oshyan