I created the fluid object from a sop level object, and it emit the fluids each frame.

I made a simple rotation animation for the object, and wanted the
fluid object inherits the velocity of the object, how to do it?

One possible way to do this, is to add the velocities from the points of the object to the velocity field in the sim. This will only chage the voxels touching the surface though.

You can use a sop_geo dop and a gas_particle_to_field dop to transfer the velocities. In the latter, you can set the compositing to “add”.

Hope that helps,
Koen

Is it a Source?

Look in the Solver for the “Source” tab, change the “Velocity Merge” to “Net New Velocity” and the Type to “Rigid Velocity” - (or “Point” if you've define point velocities instead)

Hope this helps a bit,
Jason

Or that, if you like eay solutions :-)

koen
Or that, if you like eay solutions :-)

Heh heh, I always default to the hard solutions first too.. then kick myself when I see that there is direct support for it afterward.

I found gas and fluid is not as easy as pop to use…-.-!