Theoretical: Phoenix FD and rain?

[Deflaminis]

Could you use Phoenix FD for raindrops into puddles and etc? I know it's more of a particle type situation, just curious if it could be possible.

[Ivaylo Katev]

really it's better to create the rain drops with particles, however you still can simulate the puddles with phoenix. to make them interacting create a source and exclude all the channels , only affect velocity must be on. select the rain particle system into the source and this is all. the source will transfer the velocity of the particles into the phoenix liquid, thus disturbing the surface. you need very thin simulator box, no need to cover the entire particle system, only the puddles

[Deflaminis]

This is great, thanks for the advice. If I wanted the drops to hit something, run down, and then drip, would it be the same workflow?

Thanks again,
AJ

[Ivaylo Katev]

yes of course

[Deflaminis]

Sweet. Looking to pick it up next week, appreciate your time. Thank you.

[Deflaminis]

Hello again Ivaylo.

I played around with Phoenix FD trying what you suggested, and i was able to get the particles to interact with the liquid inside the Phoenix FD Grid. I am running into another issue however that I was hoping you could help with when you have a chance; There is some odd turbulence happening on the surface of the water. As you can see in the video attached in the zip, the water surface starts with turbulence, and the turbulence seems to become less and less as it goes on. I am allowing currently 25 frames for fill up before hand, is this not enough?

the actual motion of the particles hitting the water is great in this for me. So if there was a way to remove this turbulence while maintaining the same result of the particle - water interaction that would be great. Maybe it's not possible, but the reflection chatter is a bit much for what we want to do. Thank you very much for your time.


Here's a movie file we rendered: rain drop test.zip

And here's the scene if it helps: rain drop test Max file.zip

[Neilg]

I've been working on something very similar recently, but I rendered out a top down z depth & normal map sequence, cleaned them up and made them tilable then did the raindrops in a blend material. It's still too early to show but the small tests i've done it looks great. works great for puddles and applying to surfaces that need masks. might work well for a bigger water surface too.

[Deflaminis]

That's an interesting approach. We have a couple shots that use particle flow and that seems a great way to get little splashes and drops when they come in contact with something. I wonder, did you have turbulence issues before you zdepth rendered these bad boys? Thanks for the ideas!

[Neilg]

yeah, a little. First time round it was a mess and exploded the second a drop hit it, so i gave up and had another go from scratch another day and then it pretty much just worked. still haven't figured out exactly why that happens sometimes and how it stops happening.
The thing i'm working on is in slow motion too so after dropping the time scale right down, increasing the size of the drops and doing some cleanup of the frames in fusion it came out pretty stable. still needs some work though - I plan to do another pass next week, want to try creating a material system that can handle drops running down surfaces too.
I'll do a writeup once i'm happy with the results - not sure if it'll be timely enough for you though.

[Ivaylo Katev]

what version you are using? i was unable to reproduce this initial turbulence here.

[Deflaminis]

I'm on 2.2, regular build (not nightly or anything). Would system units make a difference here? I resimmed the zip file and we get the turbulence for some reason. Thanks for everything who is posting, appreciate the help.

I wonder if a bit of surface tension would help here. I'm currently looking into a higher SPF and see if that helps, we are on classic with 2 currently, which is sort of low I guess.

EDIT: SPF 5.0 seems to have solved the problem at the beginning entirely.

[Deflaminis]

I'll do a writeup once i'm happy with the results - not sure if it'll be timely enough for you though.

Not to worry Neilg, this project is internal and there is no deadline. We're lucky enough to have some creative time to ourselves and we're making an umbrella commercial because it seemed hard/fun. It gives us a good opportunity to really put water to the test, but we'll most likely be using phoenix for fountains and rivers for viz, etc... simpler stuff. Just sort of trying to push the limits.

[Deflaminis]

Is it possible to generate splashes only when a particle hits an object inside a simulator? (Not standing water like a puddle, but more like a brick or the umbrella top?) I'm curious if I can have the water particles from my Pflow sim create a splash on a solid object on hit. After the hit it can just go away, doesn't need to run down the sides of the model or use the surface normals for anything. Crazy?

I wanted to try to replicate the splash effect when a droplet of water hits on a solid object, going upward for a few frames and then disappearing. (Not using the normals of an object to run down or anything.)

Am I better off using Pflow? I know how to do that in Pflow but I figured Phoenix would have a more realistic splash. I've attached a scene where it isn't quite working but my setup is there. Requires Box 1 (max 2014 or later).

I really appreciate the help. Thank you for your time. DROPLETTEST01.zip

[Ivaylo Katev]

yes, it is possible, set some value in the reynolds factor, it controls the splash production for the liquid geometry interaction

[luis.alcala86]

Hey Deflamis,

Just wanted to see if you got the rain system to work with Phoenix FD? I am currently working on something similar but I am using Maya and Phoenix. I would like to check out your scene but I dont use MAx. Would be awesome to see or check out the setuup for your system.