particle life issue

[itriix]

Hi everybody,

i'm essentially disintegrating a 3d city model. i've emitted many particles onto the surface with the model's color applied. I then reset the age of the particles to 0 and assigned them a random life. I then set this as my initial state of the popnet. I want the particles to be hidden and not to be effected by forces until they become part of my "emit group", which is driven by a deforming torus that grows eventually to cover the city model. That seemed simple, i just made it so that the forces were only applied to that group. but my problem arrises with the age, lifespan and the alpha of the particles. I need them to only start AGING once they have become part of the "emit group"... I thought it would be as easy as putting an AGE node after the "emit group", and setting it's source group to the "emit group"... with the $AGE variable set to $T but this obviously is wrong, because the $T variable will be a larger number as the frames progress. And therefore i'm kind of stuck. Any suggestions?

[brooklynz]

I think the " suppress rule" POP will help. You can suppress aging and other attribs like position and velocity based on membership in a group. Check out the sample files for it. You can also look at this .hip; I used an animated bounding box for the group but you might want something else. One thing to be aware of is that the default values in the suppress rule pop are variables but if you want to simply turn the suppression on just put an "1" in there or "0" to turn it off.

supp_rule.hip

[itriix]

thanks, yep, suppress node works