Re:Introduction to Position Based Fluids
by wfunction on Wednesday April 24, 2013 @01:33PM
(#5602796)
> Yeah, what you're referring to is the fact that surface tension is not scale invariant. In other words: dew can only be made of smallish droplets, not large ones.
You completely blew my mind there! I'd never noticed that before.
Does the size of a dew drop relate to the size of the particles? i.e. can we estimate the size of water molecules just by looking at the maximum dew drop size?
Wait wait wait. I was talking about the particles in this particular simulation.
Surface tension is _not_ a function of the size of water molecules. In fact you can change it quite easily just by adding a little soap.
I think the reason you see that is that they don't really simulate surface tension, but use a rather crude trick [0]. My uneducated guess is that in oder to achieve water that looks ok at small scales they would have to increase the size of the particles to the point it doesn't look smooth anymore.
[0] equation (14) of http://mmacklin.com/pbf_sig_preprint.pdf