Can Arnold volumes be deformed with a lattice ?

[andrewjmcphillips]

Hi

Thanks in advance for your help. I keep getting the error :

 # Error: RuntimeError: file C:\Program Files\Autodesk\Maya2025\Python\lib\site-packages\maya\internal\nodes\ffd\cmd_create.py line 90: No deformable objects selected.

I have a sequence of .vdb's that are inside of an Arnold volume. I want to first deform them, preferably with a lattice,  and then animate a rotation. It is a smoke plume.

As a test, I  parented the Arnold volume to a group node, and added a transform there, that didn't work either.

Although I can rotate and scale the Arnold volume, the key frame didn't work. Is this a bug in this beta?

For what it's worth, chatGPT seems to say this is possible. I can transform and constrain volumes,  but the keyframing of animated transforms is being ignored, along with any constraint.
I am on preview release 150

If it is user error, is there a workflow or any docs that I can reference for this Arnold/vdb secondary animation workflow? It makes no sense currently.

 thanks for your help

[andrewjmcphillips]

.

[sepu6 · Accepted solution]

No, you can not load a .vdb sequence and deformed with lattice. You can displace the volume, but that is different.

If you need to deform a volume you have to do it in the graph Bifrost. 

[andrewjmcphillips]

Thankyou sepu6

I am surprised that you can transform, rotate, or scale an Arnold volume with a vdb, but can't add keyframes, parent constrain or deform it with a lattice.
I wonder if other DCC's are this way.

I will look at BiFrost now. If you or anyone else has a tip on where best to look for info, lmk

thanks again for taking the time to reply

[sepu6]

Transform a volume is easy. Deforming a volume is a more complex task. As I mentioned you can do it but not with Arnold. Arnold is a render engine. You can displace your volume with Arnold. If you need to deform you can do it in Maya through the Bifrost graph or for example Houdini. Not Arnold, Vray, or Redshift. 

[andrewjmcphillips]

thankyou sepu6. I appreciate the reply

I am not looking to displace. I am very familiar with Arnold and know it is a renderer. I am looking to either constrain, keyframe, and, ideally, modify with a lattice
As I am beta testing, I do not wish to go into Houdini. I am looking to stay in maya, without going into bitfrost

I appreciate the info you provided.
thanks again

[sepu6]

Ok, then you won't be able to do that with just vanilla Maya. You have to use Bifrost (the graph - procedural system) which is inside Maya.