Hello,
Troubleshooting this issue for some of our Houdini artists…I’m not a Houdini TD so bear with me ;).
We are running a basic flip sim(19.5.569) on our farm. The entire sim is run on as a single task on a single node.
We are having an issue where the same scene, rendered multiple times(versioning up the file), yields different results on the same rendernode.
Unfortunately, I’m not well versed in what might be contributing to this.
Are there certain values on the solvers, etc. that should be set a certain way for deadline farm execution?
Thanks,-Jake
Here’s a pic of the setup to give you a general idea of what it is.
Also not a Houdini TD, do we expect the FLIP sim to come out the same every time?
Just skimming through the SideFX docs I could imagine a fluid sim being somewhat random, but I could also understand why that wouldn’t be acceptable in this sort of workflow.
I’d also ask SideFX support, they’ve got good Deadline chops and won’t get tripped up by the inclusion of our ROP.
As far as I understand it, our ROP shouldn’t be creating issues, at least here.
Hi Justin,
Thanks for your reply.
Got a confirmation from Sidefx support that this is a confirmed bug:
However, there is a known bug which is that Adapative Viscosity sims are currently non-deterministic If you turn off the Solve Viscosity with Adaptivity you may regain determinism.
I can confirm that turning this off did lead to matching output on subsequent render tests.
-Jake
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That’s good(ish?) news! Mystery solved for now at the very least. Thanks for letting us know!
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