As far as I know, particle collision doesn't work with any objects other than the plane specified by the floor. I also think that if you drop the particle emitter below the specified floor elevation for the emitters local coordinates, it won't spew any particles (at least that's something I figured when I was trying to nail down the bugginess of it on the Wintel boxes). Collision with all objects would be VERY cool but I just don't think they've cooked it up yet. Someday. -Kix

-Kix