This tutorial walks through creating a flexible fluted glass material in Unreal Engine 5 using normal maps to simulate light distortion. Instead of modeling grooves directly into the glass, you’ll use a normal map to refract light, producing realistic fluted, ribbed, or patterned glass with excellent performance.
https://dev.epicgames.com/community/learning/tutorials/V5qq/fortnite-epic-for-indies-stop-modeling-fluted-glass-do-this-instead-unreal-engine-5-step-by-step