below is an image explaining the problem i am facing i.e changing the orientation of the particles so that they align to there continuously changing speed vector
the image (right click and select view image to enlarge):

Edit: i fixed the orientation problem using physX switch to match the rotation then when it collides with a plane i send it to another physX flow event (with instanced physX world) which does not have the physX switch (to prevent it from matching the rotation due to the earlier switch operator) however i encountered another problem… how do i bind group members which are used in the shape instance operators for particles shot from birth stream operator
image (right click and select view image to enlarge)

thanks! 