Bucket "fart"?

[-greg-]

Hi guys,

I've been rendering some animations lately and on one of them I got something I call a bucket fart for lack of better technical term.

They just pop all over my renderings in a random fashion, kind of around the same spots but never consistently. Attached are 2 examples, basically it appears to be extremely under exposed buckets, some are just plain dark. when playing the animation it feels like some blocky bad compression but it's in the original renderings. I'm using vray 3.10.01 with max 2014.

I've done a lot but on a couple of models this started happening.

Any idea why?

[glorybound]

Usually it happens when texture maps are missing.

[Joelaff]

Are they the exact size of your buckets? Are you using any bitmap nodes? If so replace them with VRayHDRI nodes, as there is a Max bug that causes gamma issues with bitmap nodes.

If they are not the size of buckets check your VRayMtl cutoff values to make sure they are not too high.

There is a dr bucket render element that shows you which nodes rendered which buckets that is also useful for troubleshooting.

[-greg-]

Thanks guys. It might be related to the bitmap but when i open the files all of the bitmaps are linked. They seem to be exactly the size of my bucket and it's only rendered on my local machine. Will see if it happens again and will keep those elements in mind.

Cheers

[svetlozar.draganov]

What is the size of the buckets?
Does the same issue appear if larger buckets are used?

[Dave_Wortley]

Can be related to undersampling as well... if you make your buckets bigger it might magically work.

[Zdravko.Keremidchiev]

It might help to increase the Min. subdivs to 2 in case you are using Adaptive mode.

[-greg-]

Thanks a lot to everyone, it might be related to low sampling, I will try that and will also try the increased bucket size just in case that is the problem. Thanks again to all for your suggestions I really appreciate it