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So I have this video: https://www.youtube.com/watch?v=yq_qSWZDHHk

I'm wondering, is it possible in a scene to add a water source on top and a rigid-body ball on the floor, and with the correct viscosity and friction between the floor and the ball, would the Blender physics engine by itself be capable of reproducing this effect?

That last part is important. I don't mean if it is possible to reproduce doing the animation by hand, I mean if the physics engine itself is capable of doing the animation just by having the initial parameters.

For this it's necessary for there to be friction due to viscosity between the liquid and the ball, and friction due to surface irregularities between the ball and the floor.

Any comment is appreciated, thanks.

Edit: this question (Physics cross-simulation interactions) was posted on 2013, as well as its answer, and I wanted to see if something had changed.

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No, the fluid simulation system is independant of other simulation systems and can't interact with rigid bodies.

Rigid bodies can't be simulated with the fluid system either.

Note that the simulator is not suitable for non-fluids, such as materials that do not “flow”. Simply setting the viscosity to very large values will not result in rigid body behavior, but might cause instabilities.


A workaround would be to simulate the rigid body before hand and "simulate" the fluid with placeholder objects, like force fields or other constrained rigid bodies or hand animation. That way it would appear as if the fluid system had an effect on the rigid body.
During the fluid simulation, the rigid body has to be set as a fluid obstacle. For the fluid simulation, it is irrelevant how the motion of the obstacle was created.
The fluid can't influence the rigid body.

Related questions:
Rigid body and fluid interaction
Fluid and hair interaction

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  • $\begingroup$ But then, if that's true, is the selected answer here wrong? blender.stackexchange.com/questions/69265/… $\endgroup$ – dokasov Sep 26 '18 at 16:23
  • $\begingroup$ @dokasov You're right, worded as it was, the answer was incorrected; I have now corrected it and have also added content to the above answer. The Duplicate may be from 2013, but nothing has changed in that area (you could tediously scroll through the release notes of all versions). $\endgroup$ – Leander Sep 26 '18 at 16:54
  • $\begingroup$ I understand now. Thank you for taking your time. $\endgroup$ – dokasov Sep 26 '18 at 19:10
  • $\begingroup$ @dokasov You maybe interested pyroevil's molecular addon. With its "molecules" many types of materials can be simulated, like fluids, solids, cloth... which interact in the same simulation environment. $\endgroup$ – Leander Sep 26 '18 at 21:03

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