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Bifrost 2.2. vs. 2.1.- Aero - voxel_temperature problem

Message 1 of 4
409 Views, 3 Replies

Bifrost 2.2. vs. 2.1.- Aero - voxel_temperature problem

First I want to thank you for the awesome Update with so many great features! From what I have been testing, overall performance is improved and escape termination is just wonderful to work with. Congrats!


I have done a explosion simulation in Bifrost 2.1 and wanted to update to 2.2. The Graph itselsf has no errors, the simulation runs fine and the cache is writing to disk as expected. 

When I want to render the VDB with Vray Volume Grid, I noticed constant crashes until I figured out why it happened. 


It seems that the Aero Property "voxel_temperature" is written differently, or at leas the Vray volume grid container interprets it not as expected.

When I load the VDB in Bifrost with read_VDB_volume and check the Volume scope the tiles look normal.


As soon as I load in the voxel_tempöerature in Volume Grid in Vray, depending on the frame I currently am, Maya just hangs and I have to kill it.

The Container gets very large with the voxel_temperature property, as you can see in the attachement.


Any Ideas on what could be the problem?

Message 2 of 4

Thanks for your comments and for reporting this issue.

We will log the issue and investigate. In the meantime you can try the compound set_coarser_level_temperature_values_to_zero in the attached scene file and apply this to your aero volume before caching to disk. I don't know for sure if this will work, but the results you're getting could indicate that vray extends the grid based on non-zero temperatures.

If this compound doesn't work, another albeit not so great workaround is to cache out to bob files in and then in 2.1 convert the bob files to vdb files that you then render.



Michael Nielsen

Principal Engineer
Message 3 of 4

Hello Michael!


Thanks for your suggestion. I will give it a try in the next few days. I'm busy with another projects at the moment. 


Btw, I have a dissipation influence plugged in, which dissipates the temperature very rapidly down to zero.

Don't know if this should make any difference.




Message 4 of 4

Sounds good. Let us know how it goes, just in case others run into the same problem.

I'm not sure about the dissipation influence, you could test with and without to see if that makes a difference.



Michael Nielsen

Principal Engineer

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