Nano VDB

Hi, I have heard that Nano VDB is very powerful and I would like to import the smoke simulated in Houdini and render in Omniverse.

I have follow the document of using Nano VDB and I sucessfully import the VDB file.
However, through this method, Omniverse can only read one VDB file at a time.

For example, for 60 frames smoke simulation, I will export 60 continuous VDB files from Houdini.
Can I import these continuous smoke simulation VDB files into Omniverse? Or I can just read one VDB file at a time?
Do you have any suggested method that can import the whole simulation into Omniverse?

Thanks!

Hello @qazpolity! Thanks for your question. I need to reach out to the development team to get an answer for you. I will post back here as soon as I hear back!

I asked nearly the same question a few months ago, I was pointed to a Discord thread from last September.

A few messages later Andrew also provided a USDA file showing time sample animation of a series of VDBs.

Hope this helps.

-K

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Hi Kevin, thank you for your reply!

Do you have the file or video provided by Andrew? Would you like to share with me?

I export the VDB as USDA file and import into Omniverse.
However, I just see the bounding box of volume (which is moving by timeline).
Maybe it’s the problem of material. I have no idea how to make the volume visible.
I would like to learn how to it setup.

Thanks

Sure, file attached.

-K
PTVolumeAnim.usda (5.1 KB)

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Hello @qazpolity! After discussing this with the development team, they had a suggestion for you to try:

One way how to do this is a bit hacky but it’s possible. You have add a cube to the stage and add a OmniVdbVolume material to it. Then save the stage as usda. Open the usda in a text editor and add the subsequent vdb’s to the list under the volume material node. You’ll have to add this line where I have it in the screenshot:
asset inputs:volume_density_texture.timeSamples = { There might be a new workflow but this is how I’ve done it to this point.

Please let me know if this helps! I am going to make a development ticket to include add an ability to import multiple VDB files!

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(An internal development ticket was created from this forum post: OM-47034: Add Ability to Import Multiple VDB files)

I got it. Thanks!

Here is a script that you may be able to adapt to set timesampled vdb files:

animated_texture.py (1.4 KB)

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