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Mirco83
03-15-2009, 02:30 PM
Hi all,
Here's my first study of a water splash.
I tried to realize a correct water simulation with realflow and here's a rendering with occlusion in Maya.
I hope in many suggestions because I'm not really satisfy, expecially after I seen a simulation of a splash in Flowline gallery...
I'll give you some information on my scene:
The dimensions of the "street" si about 10 x 10 unit. The emitter is a circle of 0.8 radius. The number of particles are 200.000 and resolution 20. I set viscosity at 5 and density to 1200.
The Mesh is about 3 mil of polygons and it has a 0.4 relax filter.

So Here's the video,

http://www.youtube.com/watch?v=vCJH1XYTAes

Bye,
Mirco

ajfrank
03-17-2009, 12:32 AM
It's a good start. Funny I was working on the same type of simulation too but i never finished because i get too impatient with long (and/or slow) simulations, especially when it starts off good but it messes up during the simulation and you have to start over :banghead: .

torresmedia
03-17-2009, 09:34 AM
As Frank says, it's a good start :) Realflow is amazing stuff, so keep having fun with it. :thumbsup:

Mirco83
03-17-2009, 09:51 AM
Thank you guys,
@ajfrank: This is not a very long simulation, it takes me about an hour!

Tad Ghostal
03-18-2009, 08:53 AM
For a first attempt it looks pretty good. Any chance of it being renedered with some realistic shaders?

lewistaylor
03-20-2009, 01:53 AM
Hey Buddy,

Not bad for a first attempt. Here are some pointers.

Viscosity is way too high, even though RF is saying 3=water.
You want to drop it to about 1.8-2.5 as fluids with lower viscosity
will react quicker. Same goes for density, drop this back to 1000.

To get a nice water like flow you need to reduce your internal pressure and up your external pressure. Something like 0.01 int and 2.0 ext, possibly even higher on the external. This will help to keep the particles closer together. Closer particles=a finer mesh.

200k of particles for this type of shot is not going to be enough,
you are going to be needing 800k-1300k for Flowline/Scanline
looking fluids, and probably even more.

The increase in particles will not only impact on simulation time,
but also on meshing and rendering. I had to set up a dual boot of
XP 64 with my XP 32 just for RF and 3ds Max with 8 gig of memory.

Sounds a little daunting I know, but the results are worth it. That
being said, you can make this scene better with about 500k and
adjusting the settings I mentioned above. Tweak gravity as well,
maybe set it 10-20% higher, and generate wetmaps for your
buildings, as this will sell it more.

Another thing you can try once you've gotten comfortable using RF
is to use a script to generate spray on collision for extra chaos.

Lewis

Mirco83
03-20-2009, 10:38 AM
Hey Buddy,

Not bad for a first attempt. Here are some pointers.

Viscosity is way too high, even though RF is saying 3=water.
You want to drop it to about 1.8-2.5 as fluids with lower viscosity
will react quicker. Same goes for density, drop this back to 1000.

To get a nice water like flow you need to reduce your internal pressure and up your external pressure. Something like 0.01 int and 2.0 ext, possibly even higher on the external. This will help to keep the particles closer together. Closer particles=a finer mesh.

200k of particles for this type of shot is not going to be enough,
you are going to be needing 800k-1300k for Flowline/Scanline
looking fluids, and probably even more.

The increase in particles will not only impact on simulation time,
but also on meshing and rendering. I had to set up a dual boot of
XP 64 with my XP 32 just for RF and 3ds Max with 8 gig of memory.

Sounds a little daunting I know, but the results are worth it. That
being said, you can make this scene better with about 500k and
adjusting the settings I mentioned above. Tweak gravity as well,
maybe set it 10-20% higher, and generate wetmaps for your
buildings, as this will sell it more.

Another thing you can try once you've gotten comfortable using RF
is to use a script to generate spray on collision for extra chaos.

Lewis

Thank you for the suggestions!
I recently saw the gnomon video about Realflow and it says that for an high scale is should increase viscosity,density....So what is the real solution? Here i've a large scale...
About spray:I have the spray scripts loaded(gui and script)but i don't understand how to use them...Can you help me?
Thanks,
Bye

Mirco

Mirco83
03-20-2009, 01:41 PM
Hey Buddy,

The increase in particles will not only impact on simulation time,
but also on meshing and rendering. I had to set up a dual boot of
XP 64 with my XP 32 just for RF and 3ds Max with 8 gig of memory.

Lewis

I've a Mac Pro Workstation, with 8 GB RAM but realflow is 32 bit on osx :-(

ajfrank
03-20-2009, 01:58 PM
In my opinion there is no set in stone "real" solution. I haven't mess with a larger scale scene in real flow, only used the default or sometimes lower. But I would assume that even if the scale is larger, keeping the viscosity at it's default or lower number for water would be better as far as simulation time is concern; plus having a lower viscosity should give it a more chaotic feel, or look, to the simulation considering the liquid is not as thick. Again though i haven't mess with a larger than default scale scene before so i dont know how the simulation would act.

I agree with everything Lewis had to say except for one thing. True a higher particle count should equal better fluid quality but starting off i wouldn't have my particle count so high until you get the look you want. I'm assuming you already know that but just in case. I would start off with a lower particle count and resolution until i get the look i want and then crank it up to a high number range for when I do my final simulation.

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