Particle Age Alpha

Hey is there any way of particles fading with age? Like a ramp - texture to particle age sort of thing?
I’m currently using the attenuate by distance and blowing my particles away to fake it… which works, but only in very specific setups…

Cheers
Jason

put a point SOP after the particle SOP
in point ALPHA put an expression
1-smooth($LIFE,.5,1)
particle will fade off in the last half of its life
same for PSCALE

thats it. thanks
i was hoping for something shadery which i imagine would be faster.

any suggestions to translate 1-smooth($LIFE,.5,1) to python? :wink:

+1 on the python

don’t know about the smoothing off hand but the basic thing is just

1-me.inputPoint.life[0]

hi , thks.
I’m not able to get that to work over here. Still trying to get Python syntax to stick in my brain solidly. Doesn’t me.inputPoint.life[0] just return max life expectancy, rather than “current life left” '?

hm, didn’t test it throughly but is you use a SOP to DAT, it seems to work.

it does work , thks. hadn’t toggled from t-scrip to python on that node :0

Hey, all–

I’m trying to fade out over time, and it’s working with the Point SOP, with the technique in this post (I’m using 1-(me.inputPoint.life[0]/me.inputPoint.life[1])) to get a normalized time. However, it seems like this is really expensive. My frame rate tanks when I get a few thousand particles going. Am I missing something? Is there a better way to do this?

Thanks!

how many points?

(this can also be done with instancing and glsl)

Also for some reason, going from particlesSOP to chops, calculating the life in chop and merging the original particleSOP and the chop via a choptoSOP is more than 2x as fast as simply using the pointSOP

Heya- thanks for the reply! I don’t have a count right now, but it’s a few thousand particles. I was hoping to avoid GLSL (mostly due to lack of experience), but I know for big operations like this, it would speed things up dramatically. Thanks for the advice about going out to a CHOP- it seems pretty odd that that’s more efficient, but I believe you!