I see this is a common problem many users saw before but I couldn’t find a solution to it anywhere.
I’m getting these strange blocky artifacts when rendering VDB clouds I exported from embergen. The clouds look fine in embergen as well as the viewport but cycles renders cause them to look like this.
How can I solve this? I tried playing around with step sizes and clippings but none of them help.
Thanks, this seems like the exact same problem with cycles vdb rendering. Although I’ve seen this bug reported numerous times going back a few years but it seems there is no official fix for this bug just yet.
ye but do you also have a volume cube in the scene too? it looks like you do^^^
if the vdb is inside a volume cube (scene volume) you will still get this
I once reported a very similar visual artifact a while ago and mine was fixed by settings the transparency ray depth to a higher number (128 did the job).
But I know that there are cases that are completely independent of ray depth, but at least it might be worth a try.
If you are talking about the scene from the bugreport then the answer is - no . There is no volume cube in the scene. Read bug description carefully.
Volume intersection can be a factor, but in that case it’s not.
First you tell me that I have volume cube in the scene, then you tell the OP have another volume in the scene.
Which one is it? Be specific, otherwise what you are telling doesn’t have any sense.
no, first i said to the OP that this (his example) is more than likely the other Vol in the scene. You replied to me, I wrongly assumed you were OP for 1 message…
Aah, that clears the issue. In that case, I’m not the OP and I meant the scene from the bugreport I linked which does not have any overlapping volumes.
Anyway, excluding overlapping volumes from the equation is really simple.
The scene I posted both have a volume cube and multiple cloud VDBs overlapping each other. I haven’t observed the blocky bug with a single VDB but it does appear if 1 VDB is placed inside a volume cube.
Just for being sure you can temporarily remove the volume cube and check if the vdb alone have volume artifacts in shadow pass. Combine pass might not show you any artifacts.
So make a Bug Report. Then you know the devs have learned about the issue. As always - check for similar issues already reported before posting your own issue.