Hey guys, the (currently experimental) material layering system is going to be a huge part of 4.20 when it is released. I’m super excited for what this means for the future of material editing in UE4. There looks to be a lot going on at first glance with a couple new nodes and new assets “material layer” and “material layer blend,” but these are all not so intimidating when working at a very basic level. I hadn’t seen a video explanation really walking through the new workflow, and I thought using vertex colors as blends would be an easy way to cover the basics.
Be careful, once you start using this, you’ll never want to go back to the old way. 
You can follow along as I make a layered system with vertex colors as the blends (masks) with a simple opacity parameter slider. This is cool because you can make multiple children (sibling) instances of the parent material that all contain unique swappable materials and blend types. You could create a single parent, create a ton of children (siblings), and instantly have vertex color blends to create variation in any of your materials. Or, export your model with vertex colors assigned to areas where you want to define separate materials, and be able to change/iterate the materials assigned to each color. I only create layers and blends for RGB colors in this video, but you could add another material slot by using the alpha channel with this technique as well.
I do not cover any advanced techniques in this video, or any other type of blend mask aside from vertex colors, although after watching you should get a sense of how these are used. If you’d like me to cover any specific aspects of this (advanced masks, adding dirt/grunge maps, procedural material creation in UE, etc), drop me a comment or PM here or on YT.
This is meant to just be a jump start for someone who wants to make their first material with the new layering system. If you have worked at all with experimental material layering, this video probably won’t be much use to you. If you’d like to go more in depth and join the discussion on material layering, please visit this forum:
https://forums.unrealengine.com/deve…for-4-19/page4