locking particle position in space?

I'm running into a problem with Particular 2 that I'm not sure how to overcome.

I'm basically trying to create huge flower petals falling from the sky. I've animated a tumbling 3D object, and I'm using that as my textured polygon particle source. I've got the motion and distribution of the petals to a point I like. The only problem is that as petals are affected by air turbulence, their z position changes. This z position change is enough to occasionally move one particle in front of another, causing a jarring "popping-in-front-of" effect.

My initial thought is that I need some way of locking a particle in z space as it's emitted, but there might be other techniques to solve the problem that I'm just not thinking of.

Thoughts?

Mark Grossardt
Video Editor
Clark Creative Group