Hey guys, building a simple rain rig using attribtransfer which works great but once my particles hit the grid and the grid gets all the little white dots, they stay there forever and I don't want that, I need the cd value to disappear after a specified amount of time. any idea how I could do this?

Im learning but im still a ways away but I thought maybe some sort of expression which counts how long a prim/point has been anything but black then when it reaches a certain e.g. frame limit of 25 it turns the cd value to 0,0,0 again.

many thanks!

edit** I don't think I can use the particles $age value here as once the particles hit the grid theyre not exactly linked anymore are they so the values mean nothing?

check http://www.tokeru.com/cgwiki/index.php?title=The_solver_sop#Sop_solver_uses_in_dops [tokeru.com]

Thanks Mr.Magnus, I was using the sop solver initially but due to my limited knowledge I couldn't figure out how to then make the attribute fade. I managed to find another way by removing the sop solver and using the attribtransf do the work but this provided me with 1 frame cd values, which is the opposite of the problem I had with sop solver but then I used a chop net to lag the attribute, this way its fully controllable.

many thanks!