yeah the difference between using material layers in UE4 vs Substance, is that at runtime UE4 materials are still layered so you're still rendering every single layer in the stack, while the Substance materials are baked down to unique textures so you're only rendering the one layer.
I just don't know about using substance to change parameters inside UE4. I love using Substance Designer to make textures because of its parameters, but I always bake out from designer and bring those textures into UE4, and set up any extra parameters by hand in the material. Even if all the substances are baked at…
Using material layering only in UE4 is not practical for real game production for performance reasons on top of the limitations you mentionned. Most of the material blending doesn't need to be computed in real time, so you need to find the right trade-off between what is baked as a texture )masks+base materials+bakes) and…
you use both, bake what you can to static textures, and if you need to do vertex blending, or shader effects do that in the shaders of ue4. Its not one or the other, they go hand in hand, think of substance as a way to generate content for the material editor to work with. Use the material editor for anything that has to…
There are different cases where using substances at runtime can be useful: - Download size, if your game has to be downloaded and especially if it's free to play, you want to have the smallest game as possible and "expand" the texture package when you launch the game for the first time for example. - Customization, instead…