Hi all, have some problem: i have emitter and some particles collide with ground, what expression should i write, that this particles, after colliding with gdound - become noise ?

well if you use the collision POP then you can tell it to output the “numhit” attribute. Which stores how many times each particle has collided with the ground. Then you group the collided particles with the following expression:
if($NUMHIT > 0, 1, 0).
Then you add a force POP (noise tab) or a curlnoise POP and tell it to apply the noise only to your newly created group!

cheers,

Manu

and i dont understand: 1) i group my particles in “collision” node, then should print this expression, but where should i do this?

Here read the sticky in the particle network.

Big thanks, yet understand how it works and how use groups more powerful)

and if i want to group my particles by lifetime? expression $LIFE >2 is wrong

ouh, help is real helpful)) should type - $AGE)

$LIFE only works if the particle system know when that particle will die.

$AGE can be used as it comes along free with the particles, however if you want to actually see those values on a per particle basis, they are not inside the spreadsheet. You need to add a attribute in the popnetwork and create the $AGE variable. Once that has been done, you can look up those values in the spreadsheet.