Hey guys!
I am trying to do slowmo animation with some objects floating in space (actually maybe as they are floating in some kind of fluid, but only physically) and colliding with themselves.
If I take out the gravity entirely, the objects fly away, anyone have any ideas?

Thanks so much!
Lucia

I'm working on a space project myself at the moment, and the most sensible solution that I found was to animate the objects myself. I basically have a spin null, and a directional null. The spin null has a simple $FF on the rotational axis, while the directional null I control as I want.

It depends what you're working with, obviously if you're dealing with hundreds of individual pieces or even more like in Gravity, then my approach wouldn't work.

Hi Kays!
Thanks so much for your answer.
There will be only 2/3 object max (I am trying to do close-ups).
As I understand you are applying transform nodes to the objects?
Not sure!

I was wondering, is it a stupid idea to use a fluid simulation only for collisions but without rendering the actual fluid?

lucy
I was wondering, is it a stupid idea to use a fluid simulation only for collisions but without rendering the actual fluid?

No, not at all. The fluid sim can give fluid like motion to objects suspended in that fluid. Like bubbles in flowing water, you do not see the water, but you see its motion via the bubbles.

lucy
There will be only 2/3 object max (I am trying to do close-ups).

…but for something like only a few objects instead of a swarm of particles simply making them RBD objects and applying the right noise forces (POP wind w/noise comes to mind) would look very much like moving fluid is pushing them. Add a damping force to keep them from going out of control.

edit: ignore mass may be the default on the forces, but to have the objects collide and not all follow the force equally you would want to have the forces use mass as that would give the bodies momentum vs the flow.

So I figured I better try this out and it works pretty well. Can go with or without mass, here I am using mass but have dropped the density on the objects so the forces do not have to be set too high.

Tried it with just a regular wind force but objects would stop getting the force applied after a few frames, so I went back to POP wind which works nicely (I also turned sleep time to 0 on the RBD solver.) You can set the ‘master’ velocity with the wind and add noise to simulate the turbulent flow. By adjusting the scale of the noise against the master velocity you can give a directional flow and then have them swirl along that axis. I added an POP axis force to keep the objects from floating away from center. No need for damping it turns out.