Gravity issue

[Yannick]

Hi,

I am creating a sphere of liquid ( see this post: http://forums.chaosgroup.com/showthr...fill-an-object) I want my liquid to float in the air. I have remove the gravity with the simulation, however the liquid keeps falling.
Is there any other option I need to switch off?

Thanks,

Yannick

[Ivaylo Katev]

can you attach the scene?

[Yannick]

can you attach the scene?

Here it is:
Liquid sphere.zip
I am trying to get a floating ball of liquid, which then I want to burst which I want to see if I can do with a Maya fluid as a field (if this is possible).
I have also the problem of the liquid disappearing.

Any help would be much appreciated.

Thanks,

Yannick

[Yannick]

Hi, Have you had a chance to look at my file?

Thanks,

Yannick

[Svetlin.Nikolov]

Yup, we're on it, we'll get back to you as soon as there's a fix

[Yannick]

Yup, we're on it, we'll get back to you as soon as there's a fix

Thanks.

Yannick

[Svetlin.Nikolov]

Okay, so for now you can workaround the issue by bursting the liquid with something other than the expanding sphere - try particles. The expanding sphere does not create the right velocities you need.

[Yannick]

Okay, so for now you can workaround the issue by bursting the liquid with something other than the expanding sphere - try particles. The expanding sphere does not create the right velocities you need.

The expending sphere was just to remove it from interacting with the liquid. I need it to create the liquid on the first 2 frames.
I will burst the liquid with fields.
Also is it possible to use Maya fluid as a field on my Phoenix sim? I tried but that didn't work.

I am still having my gravity issue and also the fluid shrinks until it disappears.

Thanks,

Yannick

[Svetlin.Nikolov]

If you exclude the expanding sphere from interacting, it will not be dragged downwards by it, I think this is the gravity issue?

[Yannick]

If you exclude the expanding sphere from interacting, it will not be dragged downwards by it, I think this is the gravity issue?

Thanks,

I was using the sphere to keep the shape at the beginning, then I wanted the sphere to get out of the way in order to have the liquid bursting.

Is there a way to key frame the interaction with the sphere (container) to gradually be off? Then I can animated the burst.
When I test my scene with the sphere excluded, my liquid doesn't keep a spherical shape, it morphs into a squarish shape. (see attachment)

Sphere liquid.zip

Would you be able to provide a sample scene with a spherical liquid floating in the air?

Thanks

Yannick

[Svetlin.Nikolov]

The wobbling is an effect of the surface tension, you may decrease it or completely zero it and the shape will be kept forever.

No way to gradually decrease the interaction though. We'll see if we can make the sphere emit the correct velocities for one of the next nightly builds, but instead you can try to blast the liquid with and expanding sphere of particles instead - you have to attach them to a new Phoenix source and set it to fire/smoke mode, turn off temperature and smoke and set a strong discharge of several hundred, this should do the trick

[Yannick]

Thanks for the surface tension trick.
I manage to get the effect with my container in a layer which I animated the visibility. Just before the container disappears, I have a PheonixTurbulence kicking in.
Now I need to play with the turbulence and the grid size.

Is the surface tension the reason for the liquid to disappear (in general, not specific to this sim)?
Also is there a way to use Maya fluid as a filed?

Thanks

Yannick

[Svetlin.Nikolov]

Nope, the surface tension just tries to keep the blob of liquid together, but the disappearing can be corrected by using higher SPF and higher cons. quality (as I see you already do), and I think you should try unchecking the 'uniform density' box - for liquids it's better to use non-uniform density. If this doesn't help, try with forward transfer advection.

About the maya fluid as a field, I don't think so...

[Yannick]

Nope, the surface tension just tries to keep the blob of liquid together, but the disappearing can be corrected by using higher SPF and higher cons. quality (as I see you already do), and I think you should try unchecking the 'uniform density' box - for liquids it's better to use non-uniform density. If this doesn't help, try with forward transfer advection.

About the maya fluid as a field, I don't think so...

Thanks for the answers.

If I wanted to have the liquid to disappear in a control way, is there any option to do so?

[Svetlin.Nikolov]

I seee, so then create a geometry over the area where you want the liquid to disappear, exclude it from interacting with the simulator, create a source in fire/smoke mode and put it in brush mode, set the temperature channel to 0 (this will be the final value towards which the liquid quantity will change / temperature is the same channel as liquid in liquid more) and set the discharge to a very small number - the smaller it is, the more slowly the liquid will disappear.