Hello. I have been trying to retime a volume to about a .25 speed using the new retime sop for Houdini 17. I am sure the volume has the vel information but still I get a flickering result, kind of a strobing or stuttering feeling. I am using the advection method but I have tryied many combinations of parameters without any succes,any ideas on how to use the retime node to get usable results?

Thanks in advanced.

try using a fixed container

Thank you very much for your reply ouroboros, do you mean not using “gasresizefluiddynamic” node? I will try that out.

instead vel use density field in the retime node

As ouroboros1221 suggests, this seems to be an issue with the bounds.

Putting a volume resize node in after the volume (before my convert to vdb) and inputting a regular bounds node (with some decent padding) into the second input fixed it up for me (rendering in redshift).

See attached screengrab.

An additional follow up, I was specifically getting this with Redshift. I reported the bug and it is hopefully fixed for the next release…

Hi,

I think that I’ve found why this happens, and it is related to the fact that in your scene the velocity grids are the first ones in the primitives list and they have a variable grid resolution among the frames. I’ve have added a fix for this issue to the next Redshift 3.0 build that hopefully should resolve this problem.

Thanks for reporting this issue!
-Juanjo