Can you change the speed of a spawned particle?

In my 3D side-scroller game, I’m trying to achieve a sort of “light speed” type effect using Stretched Billboard, but one that can look different at different speeds. When the player is standing still, I want small square particles fading in and out behind them. When the player moves, the particles need to smear and start moving in the opposite direction.

The problem is that I can’t seem to change the properties of already spawned particles. I can alter the speed scale of the particle renderer to cause a smear, but I can’t seem to increase their speed at the same time. Is there any way to do that?

You should be able to change all the properties of your particles using one of these 2 techniques:

If anyone finds this thread, the simple answer is that this can’t be done with the Shuriken particle system. However, Unity’s legacy particles do give you a little bit more control via script, and this effect can be accomplished with them!