Water Fountain

[Ilmanine]

Hi,

I'm trying to create a fountain with the same look as this. I'm using a Liquid Source with Surface force but the result is a very heavy looking and mushroom top water jet. The ones on the image look like more foam and splashes then water and keep that linear shape. Also when it falls right now it makes uses waves on the base water. Any tips on how I can improve this?

Thank you

[vaya_studio]

Hey Ilmanine, as far as I remember, when doing water jets one of the most important things is to simulate the main water together with the foam, because the foam particles break-up the water jets and they look a lot better. Also, from looking at your screen shot I can tell that you need a lot smaller cell size. Hope this helps a bit

[Ilmanine]

Hey Ilmanine, as far as I remember, when doing water jets one of the most important things is to simulate the main water together with the foam, because the foam particles break-up the water jets and they look a lot better. Also, from looking at your screen shot I can tell that you need a lot smaller cell size. Hope this helps a bit

What do you mean simulate with foam? In the Liquid simulator or making the Liquid Source also emit foam particles? At the moment I don't have any because was trying to achieve just with the water

Yes this is just test resolution at the moment. I've simulated with 80M and SPF 4 and the result was the same

[vaya_studio]

Just enable the foam from the simulator, you'll have to test what values for the Foam Amount and Vel. Threshold work for your case. Simulating the water and then resimulating with the secondaries gives a different result then simulating the water and foam together. In my scene the cell size was 0.5 cm, SPF 4

https://www.dropbox.com/s/fsokzmn5j9..._v002.mp4?dl=0

[Ilmanine]

Just enable the foam from the simulator, you'll have to test what values for the Foam Amount and Vel. Threshold work for your case. Simulating the water and then resimulating with the secondaries gives a different result then simulating the water and foam together. In my scene the cell size was 0.5 cm, SPF 4

https://www.dropbox.com/s/fsokzmn5j9..._v002.mp4?dl=0

Yes that's pretty close to what I'm looking for. Do you remember your foam settings for that? Did you also have splashes?

[vaya_studio]

Here's a screen grab with the settings I've used:

[Gosho.Genchev]

One important tip - if you're using a V-Ray Material to shade the water, enable Affect Shadows on the Refraction tab. Otherwise the liquid will look dark with all the Foam particles inside.

I'm uploading a file with a fountain setup for you. A few key parameters are:

1. Noise on the phx_liquid_source node - you can use that to add randomness to the discharge.
2. The scale of the emission geometry. If you make the cylinder object thinner, the shape of the entire fountain will look more uniform.
3. The Foam Amount - too much foam makes the fountain look unnatural
4. Splashes - you could kill all the water once it reaches the top by using a Splash birth volume. I've set it up in the scene but it's disabled. Don't kill the liquid too early by converting it to splashes - there will be nothing to generate nice looking velocities for the foam particles on the way down. Instead, I rely on finding a good value for the Threshold.
Also, don't use the By Free Fly option if you have an initial fill geometry.

The provided scene file has everything to set up the fountain simulation. You just need to hook up the fountain_geo and fountain_initial_fill into the phx_sim_set, add a Phoenix FD Properties node to the initial_fill_geo and of course, increase the size of the simulator.

One more thing - keep the emitter above the water surface.

Since I can't find a video of the fountain rendered, I'm posting a single rendered image instead.

[Ilmanine]

Thank you so much both. I'm gonna try now and see what I get.

By the way what you sent me is Maya and I'm in Max forgot to mention. Is there a way you can send that in Max?

Thank you

[Gosho.Genchev]

Hey, I'm uploading a Max file.

So, key notes:
1. The radius of the water_source_geo has a huge effect - it's currently set to about 2cm. If you want a thicker jet, increase it to 3 or even 4.
2. The Noise parameter on the phx_liquid_src - it's set to 0.03. If you increase it, the strength of the discharge will vary a lot more which will case a lot of splashing. I think it looks cool but not really 'real' :}
3. The Outgoing Velocity on the phx_liquid_src - it's set to 800cm - the higher this is, the higher the fountain will be.
4. The phx_foam_shader Size parameters - I left them at their default values but if you think the water overpowers the foam or vice versa, you can use the Size Addend to increase the size of the foam particles at render time - that way you won't have to resimulate. The same could be achieved by increasing the size in the Foam tab of the simulator, though - up to you.
5. On the simulator:
5.1. The Foam Amount and Birth Threshold parameters control the amount of Foam. I've increased the Surface Lock assuming that you'll be adding water and you want the foam to float and form nice shapes.
5.2. The patterns strength and radius for the foam - you may want to edit those values - I have no idea if this will look good.
5.3.On the Splash / Mist tab - you could completely disable Splash/Mist birth to check how things will look. I think some of the liquid converting to mist on the way up makes for a nicer shape at the top but that's just me. Try it out.

Also note that on the Interaction tab of the simulator, the option is set to Include list. It's just a personal preference but I thought it's worth mentioning as you may confuse you if you start adding objects to the scene and they don't interact with the simulation.

I put the whole thing together in a hurry and haven't extensively tested things - if you've got any issues or questions, don't hesitate to ask.

Cheers.

[Ilmanine]

Ok I think I'm on the right patch right now. Just need to tune the foam and want it to go higher.

One other thing I'm trying is for the water level to actually rise so it spill outside. I've made the simulation box big enough to include it but the level doesn't seem to increase to that point. I was able to do it before with the inital fill up option ON on the Liquidsim but doesn't seem to be working with the initial fill up geo.

Any thoughts?

Thank you

[Svetlin.Nikolov]

Hey,

You'll need more steps per frame when you are simulating a container filling up with liquid - it will help keep the liquid volume so that it doesn't compress under its own weight. However, changing the steps might change the shape of the fountain...

Cheers!

[Ilmanine]

Hey,

You'll need more steps per frame when you are simulating a container filling up with liquid - it will help keep the liquid volume so that it doesn't compress under its own weight. However, changing the steps might change the shape of the fountain...

Cheers!

Ok I can try. What number range would you advise me to try? Can I just lower the res and turn off foam and splashes just to test if it happens?

[Svetlin.Nikolov]

Yup, you can turn off foam and splash, but don't change the resolution - the results will not be informative with different voxel size. Generally, use the lowest number of Steps Per Frame that would work for your setup - otherwise you'll just slow the simulation down. If I have to guess - try with 6 Steps and then adjust up or down from there

[Ilmanine]

So after 500 frames at 8 SPF it's still not filling up. I feel that the water that is coming out is only because of the movement caused by the fountain. Am I missing something?

Also at 8 steps the fountain shape looks completely unnatural

[Svetlin.Nikolov]

More steps mean a smoother surface and less detail

Then maybe you can try faking a source at the bottom - from the screenshot it looks to me like the fountain generates just enough new liquid for so much liquid spilling out, so maybe you need more liquid generated?