It is clear if one wants a descent realistic PARTICLE emitter EFFECT your gunna have to do it post edit, WHICH is problematic in it's own right! Specially with anything that needs MASKED! BUT!
IF ANY PE in carrara has an effect assigned to it such as a BLUR or an ARUA!, if it touches anything less OR another emitter the EFFECTS will be canceled out! WOW!
Also if you assign and effect to an OBJECT which is used in the emitter SAME STORY. AND if these OVERLAP with other PE your not gunna like what you see!
IE A smoke trail from 2 jet engines close to one another, WHOS PE trail will cross or even touch. THE EFFECTS will be canceled out. YOUR NICE say 12 % Blur between the 2 will have a sawtooth look of the SHAPE you used in the emitter! say a diamond!
AS far as I can tell you CAN NOT have ANY emitter objects, be them your own! OR say a diamond or square, whatever, to be emitted RANDOMLY EMIITED! such as rotation you JUST CAN'T! CAN'T BE DONE!
DO NOT USE carrara PE for anything you wish to look realistic! Post edit is your only answer! PE in carrara is a waste!