ios - Custom animation for CAEmitterCell -

i have caemitterlayer , i'd have simple animation run on course of each particle's life.

as particle pops in, i'd scale 1.2, after short time have scale 1.0 , stay way until it's lifetime expires.

i know scale, scalerange , scalespeed properties of caemittercell they're way random need.

is possible do? i've tried adding cabasicanimation (my caemittercell's name "heart"):

cabasicanimation *anim = [cabasicanimation animationwithkeypath:@"emittercells.heart.scale"]; anim.fromvalue = @(1.0); anim.tovalue = @(2.0); anim.duration = 3.0; anim.fillmode = kcafillmodeforwards; anim.repeatcount = cgfloat_max; [self.heartsemitter addanimation:anim forkey:@"scaleanimation"]; 

but doesn't work, particles appear @ random scale, don't animate @ all.

i'm not sure, seems me applying animation emitter instead of cells.

if caemittercell's name heart try this: [self.heart addanimation:anim forkey:@"scaleanimation"];. help?