To make a Laser cutting track fx:
First, prepare two textures as blow in PhotoShop:
Next, using the textures to make a material as blow in Unreal:
Then, using the material to make Particle system as blow:
What I learned:
1. Using alphaOverLife of Vector color to creat a process of movement.
(AlphaOverLife is a float distribution (should be a curve) specifying the alpha values to use for the particles.
This is calculated by finding the value of the distribution for the current RelativeLife of the particle. )