How to setup fading (trailing) beam emitter?

I’m trying to create an effect of a beam of color arcing from one actor to another where the color spreads to the target actor, but as it does this it also begins disappearing from the source actor.

This question is cross-posted to the forum here:

Attached at the above thread is a basic project example of this where a level blueprint spawns the emitter and passes to it the two persistent level actors. Current progress is using a beam emitter in the particle system with Beam Data, Beam->Source, and Beam->Target modules.

As you will see, the color pulses from source to target. But it doesn’t currently disappear from source as it moves. Is there a way to accomplish something similar to this arc with a “disappearing tail”? (Something similar to FF12 combat indicator lines.)

One potential solution considered is using a ribbon emitter. But I expect that the source of the tail will not track as the source actor moves, which is what a beam emitter will accomplish trivially. But perhaps there is a setting that could accomplish that?

Current UE version is 4.14, but will be updating to 4.16 shortly.

Any hints for other potential avenues to explore would be much appreciated.

You can do this effect in beam particle material. You would need to pan some sort of a mask along the beam to achieve the effect.

for me i selected color over life, and opened alpha over life section. I gave it a unique name and then set distribution to Distribution Float Particle Parameter. set min and max values to 0 and 1 respectively and constant to 1. In the blueprint that spawns emitter save parameter and use node set scalar parameter value and remember to use the same parameter name. then from here you can lerp float values of time and set the opacity of the beam emmiter