Fluid leaking with MassFX simulations

[stelees]

Hey there,
I have a conveyor belt and boxes stacked on it simulated with MassFX. I then put a container in each box and use that as initial fill objects. The walls of the boxes are 10cm thick yeh as soon as the animation starts the liquid leaks out through the sides of the mesh objects. I have had steps up to 24 (which basically killed the sim time) but there was still leakage. I putting a bigger object around these will be impossible as at some point the boxes fall over at the end of the conveyer and the fluid should actually tip and spill.
Is there something that is unqiue to mesh objects that are massfx objects that phoenix treats differently when it comes to walls. Should I be doing something in the sim to cater for this?

thanks.

[Svetlin.Nikolov]

I think Max passes these to Phoenix not as separate translating and rotating objects, but as one mesh with animated vertices, in which case the liquid can only react if the vertex count does not change between frames (no new objects, splitting or objects or dying objects), and also the particles have a much harder time figuring out what the mesh with the animated vertices does to them and whether it pushes them or not.

Can you share the scene so we can have a look? I hope there is something we can find to make it work better...

Cheers!

[stelees]

There is an error uploading attachments at the moment, a PHP error with temporary folder. Do you have an email I can send it to?

[Svetlin.Nikolov]

Dang, this is true, I tried uploading some empty txt and it failed. Can you upload the file via some of the file sharing services, like google drive or dropbox?

[stelees]

try this https://drive.google.com/file/d/1N-F...ew?usp=sharing

[Svetlin.Nikolov]

Hey, thank you, got it! Looking at it now...

[Svetlin.Nikolov]

Hmmm, I reduced the grid resolution to 2.116 million and the steps per frame to 1 so I can get a quicker simulation, and the liquid stays inside the box at least up to frame 60. Are you using Phoenix 4.40?

[stelees]

oh I realised that one had high viscosity as I was trying to fix it.. put the viscosity back to .1 or the like and you will see it dribble out the sides. I am on the latest nightly build.

[Svetlin.Nikolov]

Ah, using the lower resolution (2 million), 1 step per frame and 0.1 viscosity it still spills out only from the top, but then it stays in. Let me run it closer to your original settings and will report back. Will try the lower res (2 million) and 16 steps first...

Meanwhile, does it behave right for you as well with the same settings?

[Svetlin.Nikolov]

Huh, yes! At 2 million it's okay, but at 59 million some liquid particles pop up at the front of the box. Let's see what this is....

[Svetlin.Nikolov]

Hey, finally an update - check tomorrow's nightlies for a fix Thanks a ton for reporting this!

[stelees]

oh wow, this is really exciting. I loooove messing around with MassFX and have a number of examples where this failed me. This will be the nightlies of the 30th then?

[Svetlin.Nikolov]

Ah, time difference the ones from the 29th already have the fix: https://nightlies.chaosgroup.com/mai...ghtly/20210429

You should also be able to lower the steps per frame too - probably not all the way down to 1, but lower than before.

Cheers!

[stelees]

This worked way better but just not 100%. It may have to do with steps, but once I get to about 12 my machine nearly does (and actually Max crashes cause of resources) so I might just simplify my massfx stuff a bit. The boxes were tumbling when it bled through the sides so there is that part to it also, just a little too much going on.
Thanks for the fix, this is handy to know this functioning way better.

[Svetlin.Nikolov]

Oh, is there anything in the Phoenix log file? Any errors or warnings?