Event At Frame Before Collision

[kmannens]

How can I get something to happen the frame before a particle collides?

Basically, I want to change the collisionWorldPosition of a particle the frame BEFORE the collision, but based on the collisionWorldPosition of the collision.

I know I can do

float $collFrame = ((particleShape1.collisionTime*24)-1);

but how do I trigger an event at that frame?

[joojaa]

QUOTE(kmannens @ 05/05/08, 08:17 PM) [snapback]285095[/snapback]
but how do I trigger an event at that frame?

run simulation 2 times and cache the result. (what hasnt come to pass cannot be known.) Alternatively use 2 particle shapes one wich is one frame behind in simulation and reds the others data.