H15 - Velocity to Flip question

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Hey guys, i need a bit of help -
i can see that the velocitys get in to the flip container, but it does not affect the particles…. so hey what do i miss?

here is the file.

Attachments:
CarveCurve_Vel.hipnc (1.8 MB)

Janko Kissel
Maya & Houdini Smoke and Demolition VFX-Artist
http://vimeo.com/heavyatvimeo [vimeo.com]
https://www.youtube.com/user/masterheavyone/videos [youtube.com]
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-heavy-
Hey guys, i need a bit of help -
i can see that the velocitys get in to the flip container, but it does not affect the particles…. so hey what do i miss?

here is the file.

With flip you need to apply volumetric velocities/pumps/forces before the particle advection. Plug the source_vel node into solvers input3.

Also, you might want to have a look at the pop curve force Node. It got nice controls for tangent force(follow), sucktion, spin and falloff. It operates on the particle velocity so plug it in input2.
Edited by mawi - July 29, 2016 16:05:41
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Simple fix. Just wire the source_vel Source Volume DOP in to the third from the left Volume Velocity input and NOT the fourth post solve input. Any other input won't get you direct access to the velocity volume stage of the FLIP Solver. All velocity modifiers need to go in to that third input on the FLIP Solver specifically.


Important Tip: Always use the MMB (MiddleMouseButton) on all inputs of a node you are not infinitely familiar with. You will get what the developer of the node offers as a tip as to what this input should take. 9 times out of 10 you'll get it if you are somewhat familiar with Houdini.
In the case of the FLIP solver, the third input from the left MMB on that input tells you that this takes Volume Velocity inputs.

Now you will really need to cut back your velocity as you really gave 'er to see if you could get something to go.
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Ohhh damn , yeah, thx a lot. I didnt got that it does not work like with smoke sims.
and @jeff thx for these importand tip I'm surely already know, but not used
this time - its good to get remembered to those basics I forgot.
@mawi pop curve force looks very promising - I have to do a few tests to see if I
have to make my curveshapes more complex or to get enough variation only with force.

thx both of you
de Heavy

PS: what do you think, would be a good way to achieve corkscrew liquids ?
Janko Kissel
Maya & Houdini Smoke and Demolition VFX-Artist
http://vimeo.com/heavyatvimeo [vimeo.com]
https://www.youtube.com/user/masterheavyone/videos [youtube.com]
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