How to turn particle emission on/off? Is there a way to animate whether or not a particle emitter is emitting particles at a given point in time?  I'm using the particle system to animate bullets, so basically I'm trying to find a way to say: at frame 150 the gun fires a burst until frame 170, at frame 240 it fires a burst until frame 265, and so on.

I've tried key framing the particle render setting between "object" and "none", but the problem with that is that the hidden particles are still there, so when the render setting switches to "object", the particles that were initially hidden suddenly appear.

I've also thought of putting a plane (not rendered) with a collision modifier in front of the emitter and then moving it when I want the emitter to start emitting particles.

Is there a better way?
The simplest way to handle this is to add a keyframe for the particle lifetime. To make the particles stop emitting, set the lifetime to zero.

If you have very fast-moving particles (such as bullets), you will also need to keyframe the initial velocity down to zero.