Hello,

I'm trying to affect a vellum fluid sim using a custom velocity field with popadvectbyvolumes inside the solver. After a few days of experimenting and trawling through examples, I still can't get it to work. Hoping someone can lead me in the right direction with the attached file.

thanks

p.s. - apologies if this looks like a double post. I'm a new user but the first post didn't appear in the forum or my messages, so trying again

A couple of things stop it from working:

Volume Trail sop is the node actually connected to your velocity out null, you should connect Volume Rasterize Attributes instead, with Volume Trail as a side branch.

You also entered two fields in the Pop Advect by Volumes node, just enter v.

Did both those things on my side and it works.