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ssh

Water inside of air field

53 posts in this topic

This is proof of concept for simulating water inside of air field.

The only difference in simulations is the presence of that air field.

Done with standard Houdini flip tools.

Inspired by ILM's Siggrpah talk on "Battleship".

See the huge difference and much more realistic behavior.

Watch it here:

https://vimeo.com/57182252

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that looks amazing :)

love the behaviour of particles in the air

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Thanks, water with air is 2-3 times slower then just water.

Worth it.

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Very nice!

Is there any pdf available on the talk? I tried googling but it seems my google skills are failing me.

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This is excellent Sergey! Great comparison.

May I know how is this air field created? Is it some standard node/OTL that can be plugged into my DOP network?

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Very nice!

Is there any pdf available on the talk? I tried googling but it seems my google skills are failing me.

Thank you Erik, don't think pdfs exist. :)

I know it from the guys who attended it on Siggraph.

This is excellent Sergey! Great comparison.

May I know how is this air field created? Is it some standard node/OTL that can be plugged into my DOP network?

Thanks, this is very usual Flip setup with density being overrided.

Some particles(air) have very low density and some particles (water) have high density.

All is simulated in one step.

E.g. no need to simulate air first then apply cache to water or anything like that.

This is very simple setup.

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First let me say: Awesome!

Is there any pdf available on the talk? I tried googling but it seems my google skills are failing me.

Probably it was more thoroughly described in the Siggraph talk, but they also talk about it in this episode of FXpodcast

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Thank you Erik, don't think pdfs exist. :)

I know it from the guys who attended it on Siggraph.

Thanks, this is very usual Flip setup with density being overrided.

Some particles(air) have very low density and some particles (water) have high density.

All is simulated in one step.

E.g. no need to simulate air first then apply cache to water or anything like that.

This is very simple setup.

are you simulating the air field via a complete smoke solver or a stripped down version?

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are you simulating the air field via a complete smoke solver or a stripped down version?

There is no smoke solver involved.

Water and air are simulated with one flip solver.

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There is no smoke solver involved.

Water and air are simulated with one flip solver.

ahh okay I just got what you meant heh.

I'm suprised that density variaton would cause such a huge difference in time.

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Time difference is probably caused by the fact that you have to simulate much more particles.

Because all the rest of container is filled with air.

There might be way to optimize this and have air only where it's needed.

I am checking it now.

This is just a proof of concept to see how much can we get from this approach.

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As a nice side effect one do not need to do any additional tricks to get better behavior.

Which saves fx artist's time a lot.

Container, emitter, initial velocity - done.

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Looks fabulous!! Could you please explain more about the setup?

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Still haven't done proper tests, but maybe if "all we need" is the air around the sim, we can use the particle selection for the main body of water, transform to a volume, expand the volume by the amount of air we want around our sim, and then subtract the water volume with the new one, we'd get the "outer shell" of the sim at every frame, then we can just scatter into that, bring that into our FLIP sim with density 0.01 or whatever and we'd have saver all the remaining space in the box.

But maybe I didn't understand the system fully since I haven't tried it yet XD

Edited by Akabane

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I don't think that will cut it, as we would like to have the larger scale motion of the air affecting our fluid.

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I was working on it for some time.

Check it out: https://vimeo.com/60134752

Air is added only where it's needed basing on sdf of main fluid.

No bounding box needed.

One can control thickness of air shell, amount of air particles, limit air to specific hero regions etc.

Also done some extra steps to proper detect droplets with this approach.

Edited by ssh
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A hip file just with a simple scene would greatly help all of us here to understand the concept.

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I don't think that will cut it, as we would like to have the larger scale motion of the air affecting our fluid.

Check it out: https://vimeo.com/60134752

Air is added only where it's needed basing on sdf of main fluid.

Looks like I'll just have to eat my words, now =)

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This looks really good! Any more info on how to set this up? I just started learning Houdini a few weeks ago, and I can't really figure out where to start with this. Any pointers?

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I seem to be getting a hang of it. but I get to much mixing at the boundaries, like air is not rising up from inside the water fast enough and causing very noisy boundry between water and air. I wonder If you have used a sop solver to mix the trapped air particles into water particles ????

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Thanks for your share.I have tried this effect following your thought. But what I got is different. I noticed that some of your particles are floating in the air. Even if I give 0 to the parameter of the density of particles in the air, My particles also drop down . Did you control the graviety to get that effect? I love that effect very much.Please help me.

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