Exploding Foam

[themaxxer]

it makes no difference if i use or don't use B2B Interaction. The Foam still explodes.

[themaxxer]

What i found out is that Simulate Air Effects causes these Foam Chunks to exoplode. I simulated 4 Simulations 2 without and 2 with Air Effects. The ones without don't have the exploding Foam.

[George Barzinski]

Hi,

I tested the scene many times with latest night build and couldn't reproduce the issue with exploding foam (with or w/o Air Effects). Are you using the latest nightly build?

[themaxxer]

Hi there

I use the one from October the 1

[themaxxer]

Did you change any value in the scene which i sended you. I can download the newest nightly from today and resimulate the scene again.

[George Barzinski]

Nope, I didn't. Here some things you can try separately and a combination of them:
- a little bit higher foam Birth Threshold level
- reduce Falling speed parameter
- increase a little bit more FPS and Scene scale

[themaxxer]

Until now i tested higher foam birth threshold level, more FPS and reducing falling speed. Nothing helped. Tonight i test the scene scale. If it doesn' t help i rebuild the scene with all new stuff.

[George Barzinski]

Keep in touch.

[themaxxer]

Hi there

Until now it works better, that's because i rebuilt the scene with a new grid and copied every value to the new grid. Could you please tell me what are physically / realistic values for falling speed and rising speed of foam. wich resembles earth gravity? how many FPS would you suggest for a realistic scene? Is viscosity a option for a realistic scene or is a value of zero like water? Is Surface Tension a option for realistic Water or not? Do i need Droplet Surfing For a Simulation like this? I use only Foam no Splashes? Is the Wetting Value the only Option for using some kind of Friction? I Mean the Sticky Effect? Under the Dynamics Tab there is also Sticky how is this different like the one in the Wetting Tab? And what Value do you suggest for Surface Lock for the Foam for a realistic Scene? I read the Help a several Time but didn't understand everything.

Thank you in advance, kind regards David

[George Barzinski]

Hi!

Could you please tell me what are physically / realistic values for falling speed and rising speed of foam. wich resembles earth gravity?
- I would not specify concrete values for this options because it's a matter of what you want to achieve in a specific scene and these values vary. Maybe this video would make things a little more clear: https://docs.chaosgroup.com//downloa...eed.mp4?api=v2. You can check out the Beer or Coffee quick preset and investigate their options and values. I think it's a very good starting point.

How many FPS would you suggest for a realistic scene?
- I think you mean SPF. There are no specific values for this too. More FPS would make the fluid smoother and would require more time to simulate. My suggestion here is, to begin with 1 and increase it to 2, 3, 5, 12 for example and compare the results.
Check this out: https://docs.chaosgroup.com//downloa...ame.mp4?api=v2

More info from the help page:
Steps per Frame | spf ? One of the most important parameters of the simulator, with significant impact on quality and performance. To understand how to use it, keep in mind that the simulation is a sequential process and happens step by step. It produces good results if each simulation step introduces small changes. For example, if you have an object that is hitting the liquid surface with high speed, the result will be not good if at the first step the object is far away from the water, and at the second step, the object is already deep under the water. You have to introduce intermediate steps until the changes of each step get small enough. This parameter creates these steps within each frame. A value of 1 means that there are no intermediate steps and each step is exported into cache file. A value of 2 means that there is one intermediate step, i.e. each second step is exported to the cache file, the intermediate steps are just calculated, but not exported. Signs that this parameter needs to be increased are:

-Too many single liquid particles.
-The liquid is torn and chaotic.
-The streams have steps or other periodical artifacts.

Keep in mind that by increasing the Steps per frame you directly decrease the performance because more steps need to be calculated between the frames.

Is viscosity an option for a realistic scene or is a value of zero like water?
- Depends on what kind of fluid dynamics you want to achieve. Want to make water or petrol for example? Check the Water quick preset settings. If you are happy with the final result use them on your sim. I think they are pretty good.

Is Surface Tension an option for realistic Water or not?
- Every fluid has some surface tension. I think in the Water quick preset there's 0.01 input value for the Surface tension. Of course, you can set much higher or lower value.

Do i need Droplet Surfing For a Simulation like this?
- Maybe it's not necessary. I can't tell. This parameter affects the liquid and the splash particles, controlling how long a particle hovers on the surface before it merges with the liquid. The parameter is used mostly in ocean/wave simulations.

I use only Foam no Splashes?
- It's not a problem.

Is the Sticky Effect the only Option for using some kind of Friction?
- Yes, also the combination with Viscosity gives the fluid sticky and viscous (dense) look. For example, the honey would have a high Sticky effect and high Viscosity.

And what Value do you suggest for Surface Lock for the Foam for a realistic Scene?
- Check the Beach waves example scene here: https://docs.chaosgroup.com/display/...Example+Scenes.

[themaxxer]

Hi there

Thank you so much for your effort and time you invested in answering my questions. I will try this at home.
Thank you and have a good day.
Regards David

[themaxxer]

Hi there

I send you a new scene. i still got Problems with exploding Foam. I tried everything but nothing helps. I tested your advices. I created a test scene for tweaking and find out the best values. Once satisfied i copied the values to the scene i sended you... again exploding foam. Here is the Scene, can you please look at it and give me some advice. thanks in advance. I don't know what i am doing wrong?

kind regards david

https://www.dropbox.com/s/02x8zdpyc6...82%29.zip?dl=0

[themaxxer]

sorry, forgot to send you the scene also. here it is. In the meanwhile i relaxed the meshes a little bit and controlled again if the normals are flipped and all vertices are welded. they are. i would like, if it's possible to use the values i typed in. i tested the scene with different SPF and finer grids... got always exploding foam.

https://www.dropbox.com/s/ahb46g4csi...ck_NEU.7z?dl=0

[Svetlin.Nikolov]

Hey, I went back to the previous page just to check, but you didn't say if you tried turning foam patterns off - try settings the strength to 0 and ping me if there is still foam exploding.

Cheers!

[Svetlin.Nikolov]

Managed to get a foam explosion here as well, even with patterns disabled, thanks for the scene!