Hello.
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.
Hi @NuclearCactus and welcome.
Recently I found a bug that looks very similar to what you posted on the screenshot.
I encourage you to attach all your findings to the bugreport:
https://developer.blender.org/T101484
You can also check if the artifacts have the same characteristics by looking at the shadow pass of your render.
Hello
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.
If more people report it the developers might change its priority.
this is what heppens when you have a vdb inside another volume
That’s not the only case, you can see the artifacts with just one VDB object.
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.
im just saying, you can see the “god rays” from another “scene volume” in the still above they posted ^^^
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.
ye so, any overlapping volume (vdb or any other) will cause this issue for now. I think it’s just a limitation blender has with volume at the moment.
It’s a pain but the only fix i have found is doing multiple renders and comping them, or just making sure they dont overlap.
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.
Same issue, nobody cares =(((((((((((((
I have ONLY one VDB here, whats wrong with blender?
Is there any other volume that’s not a .VDB, like a world volume?
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.