Fine Waterfall mist - do I need a second sim over the top of the original

[stelees]

Hi there,
I am slowly having some success with creating a waterfall, work to be done but I feel it's getting there. BUT, I just cannot find a way to have that nice really whispy mist that you see around the flows in a waterfall and then the mist that forms at the bottom.
I am not sure if I need another Liquid source to generate foam based on the existing particles I already have or what I need to tweak in the splash and mist to generate the mist as I need it.
I saw something on youtube that said to generate mist from smoke but it didn't really explain at all how to do that.

If anyone has any pointers about where to focus my attention in the settings of my current sim, or if I need to do another sim on this sim to end up with a mist layer I would love to hear them.

Greatly appreciated.

S.

[georgi.zhekov]

Hey,

In the Splash options of the simulator you can specify how much of the Splashes will be converted to Mist. You can find more about it here - https://docs.chaosgroup.com/display/...plash+%7C+Mist

Then you can create a Particle Shader, add the Mist particles group to it and render them using the fog mode. You can find more about the Particle Shader settings here - https://docs.chaosgroup.com/display/...er+%7C+PHXFoam

Of course you can always create another Fire/Smoke simulator (after you have completed your Liquid sim) and use the liquid mesh from the first sim as an emitter for the smoke.

[Svetlin.Nikolov]

Hey, let me drop in with a couple of questions:

- Have you started from the waterfall toolbar preset?

- Can you share your settings?

Cheers!

[stelees]

georgi.zhekov - do you have a process for this "Of course you can always create another Fire/Smoke simulator (after you have completed your Liquid sim) and use the liquid mesh from the first sim as an emitter for the smoke."
Svetlin.Nikolov - yeh I started with the preset, always a good place to start and then I tweaked it. I will post a render later this evening (at my day job sadly at the moment) and will post the settings.

[stelees]

Here is an image of where I am at. I am going to have second sim at the bottom that the fall will cascade to in order to have a pooled area below. I have included a zip which is the preset I saved out of the scene I am working on.

[Svetlin.Nikolov]

It's looking pretty sweet already!

I wanna start with something strange I noticed in the preset file. There are some deprecated parameters that date back to Phoenix 2. Any chance this was an old scene updated to Phoenix 4?

I see you already have Air Effects enabled and this is what is most important. I also see a few parameters that might not be needed, but if you've enabled them on purpose, then ignore me - Droplets Surfing = 1 (maybe could be just 0), Foam B2B Interaction = 200 steps (maybe could be just 0), Foam Patterns Strength - 0.1 (maybe could be just 0).

In order to get more wispy mist, I'd suggest increasing the Mist Air Drag, but something else worries me more - I can't really see the Mist in your render. How many mist particles do you have in the Simulation rollout's Cache File Content box at that frame? Do you see them in the particle Preview (they should be colored yellow by default, but you can pick a more contrasting color to make sure you see them and they behave like you want them to)? Are you rendering the Mist particles using a Particle Shader in Fog mode? If so, are you sure the Fog Voxel Size is not too high, or the Fog Density too low?

I wouldn't got with a fire/smoke simulator yet, looks to me there is a lot to work with in the current setup.

Cheers!

[stelees]

This was a slightly older version of Phoenix, but not back to 2 I'd say about 18 months. Been quite ill and only just got back into tinkering as I need to stay on the downlow for health.

First, thanks - I will make your recommended changes.
Here are some answers
Particles - 2 897 888
Foam 1 750 279
Splashes 763 414
Mist 188 364

I just removed everything from the preview and it seems the mist is pretty much limited to just where the foam is, there isn't that pooling 'whispy' mist I am so trying to get!
I am rendering mist as fog. Voxel size is 6cm Density is 5

Cell size in the grid is 3.2cm Scene scale is 1.5
Grid size is 1795cm, 2360cm, 1760cm (x,y,z)

Does anything jump out based on that in which I need to tweak additional to what you mentioned.

Also, thanks for the compliment

[stelees]

Here is the latest iteration based on the changes.

[Svetlin.Nikolov]

Hmmm, fog voxel size sounds good, so indeed it should be about making the mist appear earlier / more easily / higher above the bottom, so it would have the time to travel sideways and get involved in the air's movement. So check here: https://docs.chaosgroup.com/display/...les+Life+Cycle. So sounds like you should increase the Splash to Mist option in order to make the splash turn into mist more quickly.

However, please also double check with the particles if the splash is created high/early enough. If it's not, then you might also need to adjust the Splash's settings to make the splash appear earlier. In a setup like this one, this should be the job of the By Free Fly option, so you should raise it (only in case you find that the splash it born too late or there are too few splash particles). I expect that the Threshold option of the Splash would not matter much for this setup, but lowering it will allow for more places in the liquid to turn into splash as well.

Hope this helps