The Flying Water Spout

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cpthomas
Posts: 30
Joined: Tue Jan 30, 2007 9:44 pm

The Flying Water Spout

Postby cpthomas » Tue Jan 30, 2007 10:31 pm

Hi Everyone!

I'm brand new to the forum, and this is my first project using Realflow.. so bear with me. :)

I'm using a spline emitter to create the effect of a "flying water stream" which travels through the air. This is reminiscant of a Sony Ericsson ad that I saw a few years ago, but can't seem to find again. But I think I've got a handle on how it should look.

Anyway, my water stream is looking a bit meta-bally, and not like water. Reading old posts, I began thinking that it has to do with scale, but I'm not sure how to remedy the situation. I want there to be little droplets of water flying around, not these big lumpy balls.... here are my settings for the spline emitter:

Resolution: 1.0
Density: 1000.0
Int. Pressure 0.004
Ext. Pressure 1.0
Viscosity 3.0
Surface Tension 5.0
Interpolation: Local
Max Particles: 100000

My Mesh settings are:

Type: Metaballs
Polygon size: 0.06

Any help would be much appreciated! I'll keep posting as I get further... I've got an okay handle on using the spline emitter (for a morning's worth of learning, at least!), so once the water looks good, I think the spot will come togther.

Thank you so much!!

My best,
Chris

Here's a link to my test movie: walltowall.com/hawaii/streamTest.mov
And a screenshot of my Realflow workspace: walltowall.com/hawaii/Realflow_SC.jpg

PS. Also, notice in the movie that the water begins to break apart and spin off at the end.. I have a feeling that had I let the move render more, it would have spun out of control. Any thoughts? Maybe seeing my Realflow workspace will give someone an idea of what's happening.

I should also note that each node in my scene has an axial speed that increases by one, so that the water gets increasingly faster.

Thank you!!


ENSLAVER
Posts: 58
Joined: Mon Jan 29, 2007 7:31 am

The Flying Water Spout

Postby ENSLAVER » Tue Jan 30, 2007 11:21 pm

Your settings seem pretty much fine, try turning Filtering on in Mesh (filters) tab and also Speed Stretching (click the + next to the mesh and select the emitter, go to the Deformation tab).

They don't add barely any time to meshing but can do wonders for the look, default settings should be fine.

cpthomas
Posts: 30
Joined: Tue Jan 30, 2007 9:44 pm

The Flying Water Spout

Postby cpthomas » Wed Jan 31, 2007 12:05 am

Thanks for the suggestion!

I turned both on, and now the water feels a little more 'relaxed.' Thanks for the tip!!

However, I'm not just trying to streamline the water... but I wish that there were droplets of water detatching from the sream and either flying away or coming back into the stream. Any thoughts on that?

Here's a link to the movie with Filtering and Speed Stretching on:

walltowall.com/hawaii/filtering.mov

Do you guys think that this is an improvement? Is this TOO streamlined? Which setting do I change to make it inbetween my two movies?

Anybody else have more tips?

Thanks!
Chris

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brandony
Posts: 231
Joined: Sat Oct 21, 2006 7:38 am

The Flying Water Spout

Postby brandony » Wed Jan 31, 2007 12:25 am

i personall would add more particles.. and make the mesh denser. its coming along though keep at it.
Brandon Young
www.byvfx.com
FX Artist | TD

cpthomas
Posts: 30
Joined: Tue Jan 30, 2007 9:44 pm

The Flying Water Spout

Postby cpthomas » Wed Jan 31, 2007 1:20 am

I'll give it a shot, thanks!

I'm currently re-building my path to be a little more interesting.

Can anyone give me a few tips on speeding up the particle preview process? I just want to watch the path in which the particles move -- not render meshes or anything. Is there a quick way to do this? It's so frustrating to have to wait for so long with so many tweaks and changes that need to be done.

Thanks!
Chris

cpthomas
Posts: 30
Joined: Tue Jan 30, 2007 9:44 pm

The Flying Water Spout

Postby cpthomas » Wed Jan 31, 2007 1:47 am

One more question,

Does "more particles" mean "more water," or just "more detailed water?"

I want there to be more water in each stream (they kind of thin out and turn wispy at points). Does that just mean to add more particles, or is there another way of going about this?

Thanks!
Chris

cpthomas
Posts: 30
Joined: Tue Jan 30, 2007 9:44 pm

The Flying Water Spout

Postby cpthomas » Wed Jan 31, 2007 3:00 am

Okay, I'm just going to keep posting in the hopes that someone can lend a hand. :)

Here's my current workspace:

walltowall.com/hawaii/break.jpg

Does anyone know why, as the water goes further, it breaks up?

Thanks!
Chris

ENSLAVER
Posts: 58
Joined: Mon Jan 29, 2007 7:31 am

The Flying Water Spout

Postby ENSLAVER » Wed Jan 31, 2007 4:07 am

It probably breaks up because of the speed and the curve it has to follow, there's lots of possible ways to fix it.. maybe make it travel slower along the spline, make the corner bigger and rounder, increase the attraction of the spline (can't remember the proper
name).

As for adding more particles (i believe he means increasing the resolution = more particles) will give more detail but ofcourse at the cost of time, with the extra particle detail you can get finer details in your mesh aswell.


For previewing probably the best way is just to lower the resolution of the particles, maybe 1 or .5, you will miss the fine details but you can get the idea. Just have to be careful as less particles means less force in areas and can lead to a slightly different result to a higher resultion sim..

hehe i can see you love RF =)

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brandony
Posts: 231
Joined: Sat Oct 21, 2006 7:38 am

The Flying Water Spout

Postby brandony » Wed Jan 31, 2007 4:52 am

more detailed water.. is what i mean there fore you will have a more conforming mesh, also try ramping up your mesh blending up to like 120, this will help the mesh stick together
Brandon Young
www.byvfx.com
FX Artist | TD

shaun_michael
Posts: 4766
Joined: Sun Sep 10, 2006 8:04 am

The Flying Water Spout

Postby shaun_michael » Wed Jan 31, 2007 3:00 pm

Hi Chris,

However, I'm not just trying to streamline the water... but I wish that there were droplets of water detatching from the sream and either flying away or coming back into the stream. Any thoughts on that?

I guess there are probably a few ways in which you can split the stream/separate particles.

1) An attractor daemon keyframed in a cunning position where it turns on and off to pull a few particles away, or even goes from positive to negative to pull particles then push them back.
2) A spline daemon, with CP radii less than the radius of your first emitter CP (which is effectively the radius of your emitter) stream, placed half in and half out of the stream could pull a stream of particles away (using the same technique as you're using with the emitter), with it's CPs positioned so that it leads the particles back towards the next CP in the main emitter.
3) A combination of the above.
4) haven't tried this, but I'm sure you could animate the radius of your control points so that in places it dips into the stream elsewhere, which might pull a few particles away.
5) May be add some small collision objects in the path (fairly hydrodynamic ones) that split the stream.
6) maybe keyframe the axial force into a negative number very briefly to push the flow away, then pull it back again (haven't tried this one either - just musing!)

Can anyone give me a few tips on speeding up the particle preview process?

If this is purely to see how the spline curve is behaving, and not the fluid, you could preview using dumb particles instead of fluid, then change it back for the final test(s)

ENSLAVER says
It probably breaks up because of the speed and the curve it has to follow

And he's right. The more speed your particles carry, the more force you need to apply to the particles to get them back on track when they hit a tight curve. This is what the axial setting is doing at each control point. However, as you'll have noticed, when you add more axial speed it accelerates your particles, meaning that you then have to add even more force to the next control point to get things back on track. Obviously this situation could get out of control with you really not having the control over the speed of the fluid along the path.

You can add a K_speed daemon to your scene, set to the maximum speed you wish your particles to travel. Now that you have control over the max speed of particles, you can really up the values in the CPs axial settings to large values. In a scene scale 1.0 with 8 CPs using dumb particles for speed of sim (so ignore the quality of the mesh) I was using values of 1000 in the axial section of each control point to get this sort of control.

Obviously you can keyframe the values in the K_speed daemon to give you even more control.

As for your settings, they look pretty good, although you may want to drop the viscosity of the fluid a little. This may lead to you having to tweak the values at the CPs in order to keep control of your fluid, but it's definitely doable.

looking forward to seeing some more WIP, or a finished spot.

Cheers,
Shaun


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