[Particle System] How to un-freeze the particles after collision

Hi guys,

I am quite a newbie to the unreal editor, and this is my first question (of many) here.

In my scene, all particles will be collided with some rigid body, and the desired behavior is these particles are frozen until some key is pressed, then they should move again under the force of an attractor.

But my trouble is, particles are correctly frozen now (by setting the ‘collision completion option’ in the collision module to ‘EPCC_FreezeMovement’); However, I could find NO way to let these particles move again. These particles are still in ‘active’ state, but it seems they are just not involved in the calculation.

So the question is: how to un-freeze these particles, so that they can move/flow as I wish?

Or, is there another way to do these:

  1. stop particles by the given surface/mesh
  2. let particles move again by the given attractor (or by giving proper speed)

Any suggestion/help will be appreciated. Thanks!