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Fluid Pump Not Working

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Hi :)

I have a simple fluid scene set up consisting of an emitter and a riverbed static object and the scene works fine, but when I set a piece of geometry in the riverbed as a pump to prevent the particles escaping the riverbed on the one side, it suddenly stops my emitter from emitting any particles at all. If I disconnect the the volume source then the emitter works again. If I am not sure if this problem is originating from the volume source in the dopnet or if its coming from the SOP level. Does anyone know why this happens or how to solve the issue?

I have attached the scene file if this helps.


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I am having the same problem, and have been trying to figure it out myself, but so far have not come up with any workarounds.

This appears to be a problem that was introduced with Houdini 18, it worked fine in 17.  The exact error message is "flipfluidobject - /obj/AutoDopNetwork/{object_name}/merge_field: Required data pump not found or the wrong type."

If you look at the "Pump from Objects" Help card, it says that the tool only works with Smoke and Pyro sims, which is a real shame because it used to work on FLIP sims as well.  It's also a little odd that they have an example image of it working with a FLIP fluid at the bottom of the help window, even though it supposedly no longer works on FLIP fluids.

I thought that perhaps the "Pump Relationship" DOP would help me make it work, but I wasn't able to figure out how to use it.

Any assistance or suggestions would be greatly appreciated!


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there were a few issues.
1) there was no velocity attribute before the rasterize_velocity node
2) pumps are affecting volume velocity so they need to be plugged in the volume velocity input of the Flip solver.
3) the FLIP object doesn't have a pump field by default in H18, you can create one and resize it.


Edited by bunker

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