particles face out

hi, i have been testing this blender particles animation.

https://vimeo.com/40368743

however, i want the particles to fade out based of his life. i don’t know how to achieve this effect. i guess i could do it with billboards, but with the others type of renderings ( objects, lines and so on).

any advice??

thanks

really useful. thanks richard. i’ll try as soon as possible. post advances here. i don’t know it this will work with object rendering. i’ll post it!! i’m testing the same effect with a smoke simulation now
thanks again

finally i have rendered with halo instead of objects or lines. i have followed the jahkaparticles way to achieve the fade out.

really greatful