Dropping object in liquid - looks physically incorrect

[Suze-anne]

Hi,

I’m a beginner in Phoenix and I’m doing my master thesis about how physically accurate large-scale simulations are already working. I compare Phoenix and Bifrost to a scenario, that I’ve filmed. It’s just a brick that falls in a aquarium (I know – pretty small large-scale). The simulation in Bifrost looked immediatly pretty close to real water. The simulation in Phoenix behaves so wrong. (see pictures) I mean this would be an result too, that Phoenix is not that far in their developments, but I’m pretty sure I just havn’t set some parameters right yet and Phoenix is able to act like real liquid. It acutally should behave like in the example Splash Amount-videos here:

https://docs.chaosgroup.com/display/...plash+and+Mist

First the surroundings of the object go up and when it sinks, the middle part goes up.

I played around with every parameter now (changed surface tension, droplets, made the stone havier – everything between 2-200kg) and also did it with another scaling. My current scaling is „from Maya“ – in Meter. In Bifrost I acutally had to do it centimenter, even tho the scene is in meters. I tried it in Phoenix too, but that looked even worse (and the water also shrinks weirdly, but I saw in the forum many other ppl had the same problem). I enabled the splashes/mist (with and without „use birth volume“), but it didn’t make any differences. The fluid just looks really viscous to me, ever paramater that hast o do with viscosity is set to 0.

The aquarium was filled thru „initial liquid fill“. I’m already using 20 steps/frame and my total cells are over 9 millions – so no very bad resolution either.

So I don’t know what to do. I’m pretty sure, I just missed some settings.
I would be so grateful if anyone could help me. Otherwise I gotta write in my master thesis that Phoenix does simulate physically correct and I’m pretty sure it does and I’m just doing it wrong haha

Thanks so much in advance!!

[Svetlin.Nikolov]

Hey,

Indeed you are missing some basics.

First, please check the info on scene and simulator scale here: https://docs.chaosgroup.com/display/PHX4MAYA/Grid Understanding the scale of the Simulator is crucial, so make sure it makes sense to you or ping us here if you have any questions.

Then I suggest you check how this scene is set up: https://docs.chaosgroup.com/display/...-DropletSplash - it's a small scale simulation that you can turn into large scale by just changing the Scene Scale setting under the Grid rollout.

You could also create your container using the Ocean shelf preset - it will set up a scene in very large scale that also uses foam and splashes.

A third alternative (I suggest you experiment with all 3) would be to read through this tutorial, skipping the pflow part - https://docs.chaosgroup.com/display/...uits+Splashing; it would still explain what and why you need to adjust.

Hope this helps!