This lesson covers the building blocks of Substrate and tackles how we can use Substrate to eliminate the common “halo” error in PBR renderers when having a non-metal material transition to a metal material. We discuss how we can change our thinking when authoring textures in external programs such as Substance Painter to provide us useful maps for Substrate.
This lesson assumes you have a intermediate level of understanding of texture creation in Substance Painter, texture importing into Unreal Engine, and Master Material creation.
https://dev.epicgames.com/community/learning/tutorials/wjnG/unreal-engine-transitioning-metal-to-non-metal-materials-with-horizontal-blending-and-substrate