In this tutorial, I’ll show you how to create a system where your fluid or smoke particles dynamically change color based on the color of an object they collide with. We’ll be using Unreal Engine’s Niagara system to achieve this, allowing you to get smooth, realistic results for interactive effects in your projects.
https://dev.epicgames.com/community/learning/tutorials/yrDGz/fluid-color-change-on-collision-unreal-engine-5-niagara-tutorial