Hey, ploughman.
First of all you need to design the particle layer. As an example, you could create a small solid with the “Circle” effect applied, and animate the circle’s color change over time (animate also Circle raduis if you like). For most cases, you will need to pre-compose that layer (because of AE’s rendering order, so that the Circle particle is “cooked” by the time Particle Playground asks for it).
Very important: Unlike the layer containing the Particle Playground effect itself, don’t make the particle layer (or pre-composition) at full NTSC or PAL size, but rather make it at just the size needed to contain your particle shape. I hope the wording is clear….
For the two cases you mention:
1) In the Layer Map section, set Time Offset Type to “Relative Random”. Set Random Time Max to a suitable time range. Relative random means picking a random frame from your particle layer for each particle, and then animating the cycle for each cell from that random point.
2) In the Layer Map section, set Time Offset Type to “Absolute Random”. Set Random Time Max to a suitable time range. Absolute random means picking a random frame from your particle layer for each particle, and holding it stil.
Hope this helps!
Adolfo Rozenfeld
Buenos Aires – Argentina
https://www.adolforozenfeld.com
adolfo@adolforozenfeld.com