I've been fooling around trying to make a realistic laser welding, but it is quite hard to make the the color on the weld fade from glowing yellow\orange to the dark gray weld when it has cooled down. The idea is to animate the welding cooling down at a certain rate. The way I have tried to acheive this, is to "spawn" a series of sphere(sw) particles along the same path as the laser beam is aiming at, and set a per-particle color ramp. The only problem is that it won't work on software rendered sphere particles. Is there a way to get around this issue?