Flip pouring into closed container?

[WhyGee]

Could you please explain what you've changed inside the flip solver? It seems to be from pre-H16 and I'd like to re-implement it in the new version's solver. 

Thanks!

[WhyGee]

I think I've found where you've integrated cWeight. I'll try to add this to the new solver hopefully I didn't miss any other changes.

Thanks again.

[galagast]

After studying Alejandro's file, I adjusted it a bit so that you won't have to edit the flipsolver HDA.

Here are my adjustments:

• Pulled out three nodes related to computing the collisionweights.
• Set the Volume Motion -> Collisions -> Volume Fraction Method to None (to disable internal collision weight computation).

So far, everything seems to still work as before

H16.0.557 - collisionWeights_v001_jlim.zip

[Atom]

Thanks for the updated file Jeff.

I am trying to get the sphere to fill up with fluid. So I added a Divergence field, but I think your Gas Solvers are blocking the divergence field from operating correctly. Do you know of a way to make the sphere fill up with fluid?

 

ap_collisionWeights_v001_jlim.hiplc

Edited May 5, 2017 by Atom

[WhyGee]

Hi again,

I've ran both setups and there is still an affect on the fluid as it passes through. I've tried playing with the thresholds but unable to get rid of this behavior and it ruins the smooth stream as expected if the container was actually opened at point of entry. Included is a preview of what I mean. If you have an idea how to fix this it would be great. Otherwise looks like the 2 stream approach is going to have to do. 

Thanks alot!

Yaniv

fill_test_v1.mp4

[galagast]

Heya Atom,

This is honestly the first time I tried looking into what the divergence field does. I've been seeing it before but never bothered using it. Thanks to you, I know now what it actually does

I adjusted the scene, hopefully it is what you were after, notes are below:

• You added a source volume that should pipe in a divergence field, but your volume path is pointing to "/obj/geo1/OUT_source".
  This source (from Alejandro's setup) does not contain volumes, it only has particles.
  So the effect is that no divergence data is being written to the divergence field of the sim.
• You could probably create a new Fluid Source SOP to generate a proper volume for the divergence field, then source it afterwards.
• Or, in the hip file setup attached below, I simply added a @divergence attribute to the particles and used the Flip Solver's "Divergence by Attribute".

So far, the sim does seem to spread out a bit more after adding the divergence.

I hope this helps!

H16.0.557 Indie - ap_collisionWeights_v001_jlim_2.zip

[galagast]

@WhyGee: any chance you could post a sample file? I'm curious why it does that.

[WhyGee]

sure

collisionWeights_v001_jlim_fill_test1.hiplc

[galagast]

I tried a couple of things, but in the end, it still had a bit of an effect to the fluid whenever it passes through the collision.
I've only minimized the effect.. check the file out to see if it is something highly noticeable.

changes/notes:

• Removed the Fluid Source at the SOPs level because particles are the only ones needed in the setup.
• Removed the Threshold Collision Weights DOP as the Flip Solver was already doing the same internally (albeit on a different sequence).
• I increased the Gas Particle to Field -> Max Extrapolate Cells, in the hopes to extend where the cWeight gets applied.

H16.0.557 Indie - collisionWeights_v001_jlim_fill_test2.zip

[galagast]

Although I'm still hoping that there should still be a much simpler setup.. If only there was a way to avoid setting up multiple volumes, and just use the existing collision volumes. Then continue with the attribute approach to set a particle as colliding / not colliding.

Need more time to experiment with this! hehe

[WhyGee]

I agree this effect should be much more straight forward.

Thanks for the hip, I'll have a look now to see how it behaves in my scene. The previous file tends to get worse when the sim resolution is finer so I hope your setup will work.

Cheers

Yaniv

[Pazuzu]

On 5/5/2017 at 1:04 PM, galagast said:

After studying Alejandro's file, I adjusted it a bit so that you won't have to edit the flipsolver HDA.

Here are my adjustments:

• Pulled out three nodes related to computing the collisionweights.
• Set the Volume Motion -> Collisions -> Volume Fraction Method to None (to disable internal collision weight computation).

So far, everything seems to still work as before

H16.0.557 - collisionWeights_v001_jlim.zip

Nice changes!

On 5/5/2017 at 2:06 PM, Atom said:

Thanks for the updated file Jeff.

I am trying to get the sphere to fill up with fluid. So I added a Divergence field, but I think your Gas Solvers are blocking the divergence field from operating correctly. Do you know of a way to make the sphere fill up with fluid?

 

ap_collisionWeights_v001_jlim.hiplc

You don't need to define a new divergence volume if you want the divergence to work as it should. You only need to activate the field in the flip object, then define the divergence attribute on the particles directly. 

Regards filling faster, you can use the same rules for the collisionWeights to define the divergence and help the fluid gain volume when is inside the collision object, also you can create particles on demand when the fluid expands, so you can use reseeding for this or create your own dynamic setup for on demand particle generation.

Here is a mod to the Jim's file that shows that, it will became unstable at the end mainly because of the volume gain, but you can animate the reseeding toggle and kill the divergence, or test the fluid volume against the volume of the collision object to deactivate the expansion, a more procedural solution.

Finally one limitation on this collision weight technique is that if you use so much extrapolation the fluid will escape at the zone where the fluid stream is flowing, all of this is because of the fluid reconstruction with the gas particle to field.

Hope that helps!

Alejandro

 

ap_collisionWeights_v001_jlim_FasterFilling.hiplc

Edited May 8, 2017 by Pazuzu

[Masoud]

On 5/6/2017 at 1:13 PM, galagast said:

I tried a couple of things, but in the end, it still had a bit of an effect to the fluid whenever it passes through the collision.
I've only minimized the effect.. check the file out to see if it is something highly noticeable.

changes/notes:

• Removed the Fluid Source at the SOPs level because particles are the only ones needed in the setup.
• Removed the Threshold Collision Weights DOP as the Flip Solver was already doing the same internally (albeit on a different sequence).
• I increased the Gas Particle to Field -> Max Extrapolate Cells, in the hopes to extend where the cWeight gets applied.

H16.0.557 Indie - collisionWeights_v001_jlim_fill_test2.zip

@galagast Hi galagast,

I checked your hip file and realized that you have edited some nodes, inside the Flip-Solver. Can you tell me what nodes have changed there?

 

Thanks.

[galagast]

Hello Masoud, it's been a while since i last saw that file
as of the moment, i can't recall the modifications i did.
over the weekend, i might have time to take a quick look.