How to prevent Mesh particles from reaching velocity = 0?

Hi All,

I have a mesh particle system (with const acceleration & collision) spawning spheres onto a platform and notice that the spheres appear to die when their velocity reaches 0 (I haven’t been able to find this documented anywhere, but it seems like a sensible feature). However, I want to control when the particles are killed rather than having them vanish when they stop moving.

I’m new to UE4 and am not sure of the best approach for this. I’ve tried setting an acceleration in the X direction (didn’t work) and damping only in the Z direction (better, but some particles still reach velocity = 0 and disappear).

Is there a way to prevent x/y/z velocity from reaching 0?

Thanks – UE4 is amazing :slight_smile:


does this happen even when the lifetime is set to zero?

Hmm my assumption (particles die when their x/y/z velocity == 0) is not correct.

Apparently, when their velocity reaches close to 0, they get “stuck” in the surface they’re rolling on (i.e. stop moving) and begin colliding with it at a rapid rate. If I set lifetime to 0 and max collisions to 300, you can see them slowly sinking through the platform (below – the rightmost yellow sphere is sinking through the edge). Some vanish during the sinking process but others sink all the way through and resume falling.

Not sure if this is relevant, but I had to tweak the collision mesh for the platforms to workaround this bug. (I squashed the collision mesh in the Z direction because I couldn’t figure out how to “adjust the collision offset”)