How can I quantize particle movement?

Question

I have a particle system of rectangles and have them moving exactly the way I want with one exception.  I would like the particles to move so that their position is quantized with an 40 px step along the y-axis each time.  When a typical object is animated, it's quite easy to add the Quantize behavior to get this effect, however I have been unable to figure how to apply that behavior to the cells of a particle system.  Is it possible?
Mike

Answer 1

Emitters are just like guns: once the bullet has left the barrel, it's no longer under your control (with the exception of physical simulations like wind and gravity.)
So, the idea is to turn off the Speed and animate the position of the Emitter itself (change the position of the "gun".)
This is an example of positioning the emitter via a Randomize behavior on the X and Y parameters of the Position:
(Any motion path will do — add the Quantize behavior AFTER any position and apply it to the appropriate position parameters.)
And these are the quantized positions:
In order for quantization to work, you cannot exceed the frame rate of the project with the Birth Rate of the emitter (or you'll get 1/2 positions, then 1/2 and 1/4 positions, etc...)  To get around the Birth Rate limitation, duplicate the Emitter and change the Random Seed on the Randomize behavior.
Hope this helps...