Exposing multiple particle system color parameters on a blueprint

Technical & Engine Help Unreal Engine Help
#1

Hi! I’m new to Unreal and hope there’s an easier way to do this.

I need to expose 2 (or more) color parameters at the blueprint level that lerp in a cascade particle system. Either of those colors can be changed to create blueprint variants.

Here’s what I’ve tried and the drawbacks I’ve found.

1. Scale Color/Life. If this is set up as a particle parameter, it only exposes a constant on the blueprint, but I need a constant curve.

2. Dynamic Parameter. Used a dynamic parameter in the material to drive the color values. These all got exposed at the blueprint level and would have been a great solution if I could have more than 1 dynamic parameter per emitter.

3. Color Lerp in Material. Adding a ParticleRelativeTime color lerp in the material will expose colors on the material instance. Every time a new BP variant is created, all the material instances that need different colors need to be duplicated. This isn’t great when a single particle system can have 10+ material instances. Since it also isn’t at the blueprint level, I created a blueprint to run through a particle system, find all materials, and replace the color values, but the logic gets expensive, especially for every effect on a mobile game. It seems like there’s a better way of doing this.

Are there any other ways of achieving this within cascade/materials/blueprints?

#2

How many different colours/combinations could you potentially have?
You could create a curve library, in the particle, lerp between 0-1, then in blueprint set which curve to sample on, then in the material, you just take the curve and sample at your particle 0-1 range to decide the colour?

#3

This is a cool idea, but if we allow players to choose colors, even from a limited palette, it could be hundreds or thousands of combinations. Definitely need color parameters exposed to change these on the fly.

#4

Ended up using your suggested curves as well as simplifying the blueprints! Didn’t know you could sample curves in the material like that! Thanks @Niels

1 Like
#5

For anyone who comes across this, I basically set up what’s explained here: