VDB bounding box generates weird reflection

[darksoul]

Hello Corona Team,

I created a smoke simulation in c4d and exported to OpenVDB format. I imported this into Corona Volume Grid, which plays the animation nicely.
The problem is that the smoke is flowing into a glass tube and the Corona Volume Grid Bounding box is sometimes smaller or bigger than the glass tube (the size of the box changes with the simulation), which generates an error in the glass reflection.

What could be the solution to this?

(C4D R21 + Corona 10)

Thanks a lot for the advice,
Have a nice day
ds

[Beanzvision]

Hi there, are you able to share you scene with us? If so, please use the link in my signature below.

[darksoul]

I had to create a simplified project because I have a confidentiality agreement for the original project file. I've uploaded the file to the link in your signature, the issue is clearly visible there too.

I really appreciate your help :)

[Beanzvision]

Hi, it seems that the vdb is clipping the inner wall of the sphere, can you try to slightly raise it to a point where the artifact is gone? Depending on the job, it might need to be lowered or slightly scaled down a little.

[darksoul]

Unfortunately I can not move it, or scale it down because it's a technical animation, the smoke has to be exactly there and has to fill the given space. So it has to be perfectly fitted there. :/

[pokoy]

Just tested this in Max (Corona v9 here but seems there are no differences between v10 and v9 and how they handle this) and it's the same problem - this is a bug.
We've spent so many cycles asking for volume rendering improvements and fixes - it really needs to be addressed so that it finally works without headaches. Suggesting to avoid VDB volumes cutting through other objects is clearly a non-advice - please make sure this is acknowledged and fixed. We really need volumes and VDBs to work flawlessly.

[darksoul]

Thank you so much pokoy, I tested this in Cinema 4D with Corona v7-8-9-10 and the reflection is wrong everywhere.

[aler]

We really need volumes and VDBs to works flawlessly.

+1

[burnin]

Hmm... If only, "Volume priorities" control would be up to the user/artist.
No other engine has such limited and so buggy approach.
+1

[Beanzvision]

(Internal ID=1233026467)