Just got some idea using Ramp Parm for altering start and end of particles forming and affect them Max and Min. I know that parm VEX has Key Position & Key Value, which are float array. Is it possible to use it for phasedly adjusting? Or any other options?

There is a Min and Max vop and vex command that should give you what you want.

Thank you Ratmann but I cloudn't get your idea…
Does it mean controlling float array data with vex script? It seems Min & Max VEX don't work with float array in Ramp Parm…

auratuslemma
Just got some idea using Ramp Parm for altering start and end of particles forming and affect them Max and Min. I know that parm VEX has Key Position & Key Value, which are float array. Is it possible to use it for phasedly adjusting? Or any other options?

Maybe you just need a fit vop with a start / end frame parameter values to create an attribute that's 1 or zero between a frame range.

Rob