Losing my nerves with rigid bodies simulation

Hi. I have been trying almost all…This simulation is killing me…

I am doing this tiny drone carrying balls inside a container…the balls are kind of levitating and constantly moving. The drone is parented to an empty and the empty is following a curve to guide the trajectory.

I am also animating the gravity to help the balls go up and down…and I am using 100 steps per second and solver iterations…

It is the only thing I need to finish this small animation…and it is taking me many days to solve the scene where the balls are being carried and drop inside a hole…

Please if you have some tips to give…
I can also share the file via DM

Hi I have more information.

I manage to make the scene start kind of ok:

As you can see the balls don’t follow the container moving towards the factory behind.

The “transport” system is parented to an empty following a curve.

The balls are not. They should be following the transport trajectory by being push when the container moves along with the drone.

Balls setup:

Container setup:

Container Rim setup:

Container Door (this one is animated and when it turns in the end of the trajectory the balls should be released from the container:

The Rigid Body World panel looks like this:
The gravity has keyframes…to help in the oscillation with the balls.

Ok, so correct me If I am wrong.
You have the balls levitating inside the container and you want it to be carried over to the other box, open the door below and have the balls fall out, but the physics are wonky and not following correctly?
Does it work without the movement of the drone container?
If the answer is yes, then you could just keep the drone in place and animate the world (everything else) coming towards the container.
Sounds like a stupid hack, but its actually the law of relativity applied correctly.

1 Like

Yes you got it correct. The balls levitate and do what I want when the rig is not moving.
The problem starts when I move the drone towards the factory…
I could try to move everything …but that will change lighting from hdr I guess and my simulation with smoke…It sounds quite tedious…

I just want to understand if I am missing something or if this has to do with blender not being capable of simulating rigid bodies beyond filling boxes when we dont have animations…
I am considering trying STORM…but its paid…
and this is just a personal project

Thank you

I don’t think that will affect lighting, if you cache the smoke as vdb you can move the vdb container afterwards.
I don’t think it’s that tedious if you parent everything under one empty and move it together.

In regards to the physics. I don’t have much experience with Blenders system, but in my general experience with physics system in other programs, they all don’t like container carrying many other objects inside.
At least not out of the box.
So the easiest solution is always to cache their movement in place (maybe just calculate the rotation of the object) then move it as a whole around, constraining the simulation and using passive and active states that you can control better.
BTW, what happens if you parent the balls to the transport system?

Oh, did not try to parent the balls to the empty! Maybe thats it…I will try …The balls are all in a collection do you know if I can parent a collection to the empty?

No. You have to use an empty AFAIK. Collections have no transform and can’t be moved in itself.

Ok I will try to parent them and upload a simple viewport animation