Perpetual particles?

[avpromedia]

How do I create a screen of particles that's evenly distributed, slowly drifting around with no overall direction, and has no obvious birth and death? The particles can drift off screen but new ones need to drift on screen to maintain a constant particle density.

Think of this as top view of particles in a suspension (without seeing container walls).

The "no birth and death" can be done by setting an initial birth rate and then keyframe it to zero after the screen is filled with particles.

But I haven't figured out how to do the "no overall direction". If I turn off gravity the particles just hover near the emitter. If I turn on the gravity and then turn it off after a while like I do with the birth rate, the particles continue to drop downwards, as if they inherit the gravity at birth.

Any ideas?

[Mylenium]

You have not given us the most important information: What particle system you are even using.

Mylenium

[ShiveringCactus]

Guessing you're using CC Particle World. Particles have their gravity set at birth, altering it only affects new particles.  Try putting a wiggle on the velocity to generate randomness and mess with the Physics types.  Fractal Omni is pretty good for a more organic distribution.