I'd like to change the visual of the particle effect according to the movement speed of an objet.
High speed = higher rate and lower timeout -> the visual result is bigger and fits the speed feeling.
My problem is that when I decrease the timout (since the speed is decreased itself), the particule generated before the speed decreasement are visually killed, they don't die "naturally" and... it's not very appealing.
How would you do that smoothly? It is possible to let the "old" particules keep their own properties and die naturally while new particules with new properties are generated? (and will die with their current properties)