View Full Version : Moving obstacle won't interfere with fluid body.

05-Jan-10, 15:48
I'm starting to experiment with Blender's fluid simulation and want to animate a projectile piercing through (displacing) a floating sphere of water.

I have Created the domain, encapsulating the whole scene, a sphere serving as the source mesh for the fluid, and a projectile that i have animated to move through the sphere, whilst rotating.

Big Box -> domain
Sphere -> fluid
Projectile-> obstacle (tried Shell and Volume)
No gravity.

When i watch the baked result i can see that the projectile hasn't interacted with the body of fluid at all. The fluid itself seems to be calculated without error though, slightly wobbling about.

Here a screenshot (http://i48.tinypic.com/102va5d.jpg) of the problem.

I've seen Blender animations of this kind, so i assume it's possible. I'm using the 2.5 Alpha.

Any help appreciated.

05-Jan-10, 17:34
Well it looks like it interacted somewhat doesn't it? I see fluid drawn along with the bullet at its base. Perhaps if you slowed down the bullet and increased its friction it may help some. Also try it with something that is not so airodynamic like a cube, that should push more.

06-Jan-10, 11:22
The screenshot might give a false impression, but i've tried this with large chunky objects and the same applies. Blender throws no errors and happily bakes away, but the obstacle isn't included in the calculation.

Could this be a Blender 2.5 issue? I assumed that despite being an alpha release, all its core functions are working already. It sounded like that from the download page.

2.49 is very hard for me to use due to its big difference from other 3D apps, so i don't want to go back to it if possible.

Philippe M.
06-Jan-10, 12:09
hey PrinceVince :-)

is the object turned on as an Obstacle object in the Fluid panel? if you activated the normal Collision, which works for Cloth and Particles and stuff, then i think it doesn't affect the Fluid...

Richard Marklew
06-Jan-10, 12:36
Stick with 2.49 for fluids. Blender 2.5 alpha0 is named alpha for a reason, many things have not yet been implemented including some of the fluid simulation features.


06-Jan-10, 13:56
I just recreated the scene in 2.49 as best i could, and voilą - it works! So it's a 2.5 limitation for now. If i can create anything interesting, i'll post in the WIP section :D

Philippe M.
06-Jan-10, 15:09
If i can create anything interesting, i'll post in the WIP section :D

ooh, cool :-D can't wait to see those interesting things :-D and your future blender projects too :-D

Happy Blendering! :-D (2nd time i've used that expression :-D)