Control of emitted amount of fluid

[Macha]

With Volume fluids, where do I control/animate the amount of fluid emitted by a fluid source?

[wolf_cub_one]

With Volume fluids, where do I control/animate the amount of fluid emitted by a fluid source?

There are several controls available for you and it depends on your setup. If you have just a single fluid object being use then it's based on the size of the object being used as the fluid. However, if you have a source and/or a pump, then you not only have control of the size but also the rate of the flowing fluid. The Motion DOP will have the controls you'll need. If you use the shelf tools then it's automatically setup for you with the name setsourcevelocity. You may need to unflag the Bypass on the node depending on the setup. Then just animate your velocity.

HTH

[pclaes]

Or... you make your own custom field that copies however much density/temperature/velocity you want into the simulation.

If you have not yet read it, it might give you ideas:

http://www.peterclaes.be/tutorials/pct_0007.pdf

[Macha]

I attached a simplified file to illustrate my problem. I would like to be able to control the fluids flow rate as well as collision (with rather more complex geometry than in this example).

I can't figure out a good way to make the fluid collide with the surface below. It flickers, it disappears, it doesn't collide... I don't know where the problem lies.

I can get it to work with the particle fluids, but as soon as I upscale the whole thing (more emitters, more geometry) it always explodes, breaks and falls apart.

So I am trying volume fluids, but that's hard to control as well.

Where am I going wrong?

exampleFluid.hipnc

[Solitude]

I attached a simplified file to illustrate my problem. I would like to be able to control the fluids flow rate as well as collision (with rather more complex geometry than in this example).

I can't figure out a good way to make the fluid collide with the surface below. It flickers, it disappears, it doesn't collide... I don't know where the problem lies.

I can get it to work with the particle fluids, but as soon as I upscale the whole thing (more emitters, more geometry) it always explodes, breaks and falls apart.

So I am trying volume fluids, but that's hard to control as well.

Where am I going wrong?

Looks like you just need to increase your divisions. In the 'liquid' node inside of your dopnetwork, you can increase the number of divisions, which gives the sim more voxels, and thus a higher level of detail which will help get rid of the dissapearing liquid.

[wolf_cub_one]

Looks like you just need to increase your divisions. In the 'liquid' node inside of your dopnetwork, you can increase the number of divisions, which gives the sim more voxels, and thus a higher level of detail which will help get rid of the dissapearing liquid.

As Soliutude suggested, you'll need to increase your divisions, but this will ramp up your simulation time and it'll need a very high resolution to get what you want. I would suggest using a combination of volume fluid and particles to do what you are looking to accomplish. The volume fluid will serve as the main body and the particles will serve as the fine detail dripping fluid. I'm a little rusty so hopefully someone else can fill in anything that I might have missed or correct any mistakes.

You already have the basic setup. You'll need to write out the vel(velocity data for the volume fluid). If you look into the fluid_surface node it is visualizing the surface(surface/Visualization). What you want to do is copy this DOP Import node and set Geometry Data Path to just vel. Then write this data out as a bgeo sequence with whatever amount of frames you'll need. Make a new new geo node with a file node inside to read this velocity data.

Next you'll need to set up a popnet that will act as your particles that will flow down and hit your collision object. Hopefully you can do this yourself. The important thing is that you'll add to your popnet an Advect By Volumes node. This will help you drive your particles based on the motion of your volume. You need to direct Velocity Volumes to that geo node that has your velocity data. You also need to change Advection Type to Update Velocity to get it to take this velocity data. If everything is done correctly, you can now blend between the volume motion and the particle motion by playing with Velocity Blend. That is the basic setup. Hopefully, I did not miss any steps. Please correct me if I'm wrong.

HTH

[Macha]

Wow! Thanks wolf-cub and Peter! That is quite a beautiful and elegant solution!

It works super-well on the small example. I'll see if I can upscale it now.

Edited February 13, 2010 by Macha

[wolf_cub_one]

Wow! Thanks wolf-cub and Peter! That is quite a beautiful and elegant solution!

It works super-well on the small example. I'll see if I can upscale it now.

No problem. Please post the result of your final work.

Got to go and watch some NBA.

cheers

[Macha]

Argh...unfortunately it doesn't work when I upscale it. My fluid box isn't very big (4^3, something like that) but I can't get the divisions much higher than 40. After that it simulates 10 hours a frame! It is too low for a good enough velocity field. It is not a memory problem (stays below 2 Gb RAM) but my collision (pre-saved sdf) is quite complicated. I guess that where it hangs.

So, I am falling back on a pure particle solution, unless I find good trick to upscale particlefluids.

Edited February 15, 2010 by Macha

[wolf_cub_one]

Argh...unfortunately it doesn't work when I upscale it. My fluid box isn't very big (4^3, something like that) but I can't get the divisions much higher than 40. After that it simulates 10 hours a frame! It is too low for a good enough velocity field. It is not a memory problem (stays below 2 Gb RAM) but my collision (pre-saved sdf) is quite complicated. I guess that where it hangs.

So, I am falling back on a pure particle solution, unless I find good trick to upscale particlefluids.

When I first read this post, I thought there must be something wrong. I had to reread it to realize that you were using particle fluids. Would it be possible to get an updated scene file? If not can I get an animation or image of this complicated collision?

I'm sure someone will have another possible answer for you.

good luck

Edited February 15, 2010 by wolf_cub_one

[Macha]

Nono, I was trying both. Particle fluid and volume fluids.

Bit hard to explain what I am doing doing without spoiling the fun of watching it when it is done.

Well I'm rendering now, maybe it'll be OK and I can post it soon in the WIP for suggestions.

[Macha]

Here's the WIP relating to this problem: