Trapcode Particular

Physics group > Physics Time Factor

In the Physics group is an interesting control called the Physics Time Factor. This parameter enables full control over physical time. The particles can be made to move faster, slow down, completely freeze or move backwards. Better yet, the camera is fully controllable so it can move around in the Particular scene.

The Physics Time Factor control in the Physics group. 

How Time Factor works

To freeze time, the Physics Time Factor parameter has to be keyframed down to 0. If it is simply set to 0, no particles will ever be born. You can keyframe from 0 to another value to make the particles move again. Higher values make the particles move faster.