If you have a plane used as the clone emitter, and you use the Shader effector to decrease the number of clones along its length, this works, but the original number of clones are still actually there (in memory); they just aren't visible.
Is there a way to only generate the ones that the shader effector allows to be visible? (or uses some other method of population?)
I've got a horizon shot where the number of visible clones that (set with an even distribution), go off into the distance and the number of visible clones, as they get farther from the camera, increase exponentially, simply because of the angle of the camera view is taking in more realestate, and thereby more clones as the distance increases, but you don't actually need all those clones once they get far enough away. But the forgeround ones need to be of a certain density - the background could get away with far less.
In the past I've used multiple emitters with decreasing densities, but I've always wondered if there was a better way.