Liquid Sim - scene scale parameter doesn't work

[ominetpl]

Good afternoon everyone!

First of all I'd like to say hello to community, as this is my first post on the forums

Just a quick question about scene scale parameter - actually I can't see any difference when changing it.
I've made some quick tests on simple scene with just an emitter - whithout any additional forces and gravity = 0.0.

The same scene is simulated with scene scale value = 1000 and 0.001.

Is it a bug or am I doing something wrong?

Thanks in advance and thanks also for superb software

[georgi.zhekov]

Hello,

When you are using liquids without gravity this is expected. If you turn on the gravity you will see a difference.

[ominetpl]

Thanks for quick response!

So does it mean that scene scale affects just the Std. gravity and doesn't affect liquid characteristics at all?

I've just messed with all the stuff like viscocity, surface tension, non newtonian, added max wind and gravity and still don't see any difference while changing Scene scale.

It looks like it's just a multiplier for the gravity. Should it be like that?

[Svetlin.Nikolov]

Hey,

Using defaults for liquids, you won't see much difference - it does affect some more parameters when you are using fire. The scale affects the gravity, sources in Inject mode, the cooling of fire, foam and splash dynamics and the surface tension, but the gravity is the most noticeable one

Cheers!

[ominetpl]

Ok. All is clear now!

Thanks a lot for answer.

Cheers.

[Ivaylo Katev]

both the viscosity and surface tension are not affected by the scale, for the viscosity this is pretty normal, the surface tension should be, but we made it independent intentionally, many users are confused by the scale dependence.

[Svetlin.Nikolov]

Yup, that would be the Surface Tension only for the PHXSimulator liquids - the LiquidSim does not depend on the scale for Surface Tension.

[ominetpl]

Thanks a lot guys!
That makes everything clear to me!

[im.thatoneguy]

How then do you simulate small scale effects where cohesion becomes an exponentially stronger force? I feel like the surface tension ranges of 0-1 doesn't take into account something like a raindrop which will actually bounce off of hydrophobic glass.

[Ivaylo Katev]

you have to adjust the surface tension by hand to have small scale effects, in the most cases such sims are arranged in large scale with surface tension on, this produces final effect of slowed down small scale simulation
of course the surface tension is not perfect, actually this is the harder part of the liquid behavior, our solution is fast and limited, we have to extend it in the future, but if one adds everything at the beginning, the release will never come