Physics objects freeze

Hi - I’ve got some physics objects (ammo) with a mass of 0.1 in a world with gravity -0.3y and inside a boxed area of static rigid bodies with 0 friction - and I apply an occasional upforce to the particles to find that they often get stuck in mid air around the top of the box, and won’t come down until they are hit by other particles.

Any idea why this might occur ? Do particles go to ‘sleep’ if they’re moving very slowly .

Hi @jerryComo! Based on what you say I think the gravity in combination with the force is not enough to move the particles. After a collision of another particle, probably sufficient force has been applied to make them move again. Have you looked at the results with different values ​​or removing the static objects?

What are the restitution values of the static bodies and particles? It could be possibly that they are losing enough momentum from impacts that they have such a low velocity for long enough to be removed from the simulation for performance purposes

I need the static objects to constrain the physics objects - so I’m currently listening for the particle when they go to sleep in mid-air and giving them an applyForce to move them on their way. It isn’t ideal, but it’s better than the total freeze.

thanks for the reply !

restitution and friction is zero → 0.1 in most objects in the scene as I’m simulating snow globe particles so don’t want too much bounce. And yes it’s deffo the low velocity that is causing the impromptu sleep state activating.