Liquid UVs

[joshclos]

Moving, deforming textured liquids - Is it currently possible to do this (see links) in PhoenixFD?

https://vimeo.com/108410988
https://vimeo.com/64964458

I searched around the forum and I see answers regarding the RGB channel combined with the Phoenix Tex Map but I haven't been able to get that working with a very simple setup of an initial fill container. I saw a studio actually switch from Phoenix to Realflow to gain this feature alone so I'd love learn more.

[georgi.zhekov]

I have made you a quick example scene how this works.

The file was made in Max 2017 but it should work in Max 2014 as well.

[joshclos]

This setup does not seem to deform the texture though. I'm attempting an effect exactly like the above references where the liquid mesh is textured, and once the liquid moves and deforms, the texture also deforms. This setup seems to be a projection of the texture that is always coloring the liquid like a clean checker. It also does not seem to update in viewport which is mildly challenging to work with.

Thanks for your help!

[Svetlin.Nikolov]

Ah, we don't support deforming UVWs currently. This produces pretty bad results when the liquid gets very stirred up. We must try to implement this again and see where this leads us (Phoenix did support this in the past, but it was dropped).

Right now, you could theoretically get a close result with little or no RGB diffusion and huge res...

[joshclos]

Thanks for the reply - I'm interested to test the theoretical solution you mentioned just as an R&D thing. Does it work by assigning a color on a per-particle basis and have no RGB diffusion so they don't mix colors? I'd like to do a test of this to see what it looks like. I'm not quite sure how to assign the colors to the particles just once and not continuously.

[Ivaylo Katev]

the liquid bunny looks like colored particles, but the another ref is more interesting, looks like reversed simulation

[Svetlin.Nikolov]

Yup, the guy from the vid says that what's used was a backtrace of the UVWs, so maybe this is why the UVWs are mixed in the beginning when the liquid moves faster and then texture seems to straighten out as the liquid settles. Not really sure how this has any practical application, but it's an interesting tech demo nonetheless...

[joshclos]

Yea the backward UV mesh technique is pretty cool but since we don't have mesh UV mapping anymore, I'm gonna go after the particle color method. What I'm wondering is how to use the particle-color method in phoenix. I attempted to do this using the example scene Georgi sent but the particles seem to constantly re-assigns the color instead of keeping their color at the time of emission.

[Svetlin.Nikolov]

Hmm, what if you drop the RGB diffusion to zero? This should help.