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Helicopter+Dynamic FLIP Waves Test


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Strongly based on (mighty) Igor Zanic old Naiad test of an helicopter, I worked on this test to get the hang of the new Ocean FX tools in Houdini, as well as testing how to use custom forces to affect FLIPs (to simulate the helicopter blades).

Sorry for the somewhat grainy render and some Nuke retiming flicker around. I didn´t have the time to retime and re-render. I think I make up for this with an interesting test.

My conclusion so far is that it´s very difficult to use dynamic waves and still keep your main effect strong and controllable because of the amount of interactions going on with the waves. The reason being dynamic waves require a really huge container not to come back too soon and this adds up on the usual problems on any similar scene.

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  • 2 months later...
  • 10 months later...

How many ways are there to make a fluid velocity pump in Houdini these days...


Here is a quick mock-up of a pump force wind wash object to simulate a fan force from a helicopter. Just parent this to your animated object.


Quick hack prototype using Volume VOP to sculpt velocities from a tube feeding a Fluid Source SOP set up as a pump.  Used the sdf surface field for some outer edge feathering on the pump velocity.


I also properly pre-multiplied the pumpvel field by the pump field to get a good mask.


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Pumps are an efficient way to modify the velocity field in any of the grid-based simulations: FLIP, Liquid, Pyro, Smoke. 


The Fluid Source SOP has that pump preset and works in concert with the Source Volume DOP in the DOP network feeding sources in to the various grid based solvers.


If you want, you can always dive in to the Source Volume DOP and walk through the various Micro-Solver DOPs used to compose that node. Then use those techniques to add any custom micro-solvers to any grid based solver. No need to do that though. You will find some Houdini enthusiasts who will use micro-solver DOPs to expose various workflows but for the most part, they are replicating the behaviour of the Source Volume DOP.

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  • 10 months later...
Hello everybody =)
I aske my question here because I asked a question in a new topic but no answers
I would like to know how can I have the radial wave effect (look like white foam in main fluid) of this video :
I tested normals to velocity and see the OldSchool file with pump as propellers but no propagation effect.
I'm learning houdini with exemple file of sideFx and documentation. Can you give me clarification about some details please?
- what's the real different between "particle velocity" "volume velocity" and "post-solve" input of flip solver? Volume velocity is for add microsolvers? post-solve to remove or add particles using Source volume?
not clear in my mind.

In the file of OldSchool :
- the Source volume, what's the difference in Initialize category :

- Source Ocean Layer
- Sink Flip
I searched in the documentation but don't found the definition of each choice of initialize category
thank you, I think It's already many questions.
Answers will be very helpfull =).
Edited by dofe
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