This session was held at Epic's booth. The speaker wasAlan Willard.
It is currently very challenging to adjust current material attributes, and developers could break other shaders or characters that are using them.
Material Layering is a new way to combine materials in a stack, which builds out the correct material graph without needing to build the node graph by hand. There are two new asset types that we use to do this:
Material Layer Blends
Functionally, these behave similarly to Material Functions. These new asset types also enable you to create child instances, which you could not do with Material Functions.
Material Layer assets have a default input node which pipes base Material Attributes in from the Material. Material Layer Blend assets have two default input nodes which enable you to access the Material Attributes from layers above and below.
New material layers are built and structured like Photoshop and can be easily modified and moved in the stack. Assets are also easily shareable, and the artist can pick and choose any of the layers. This allows artists to make changes to one character without having to worry that it might impact other characters.
Drag and drop capabilities are available for moving stacked layers, and all layer attributes and values are located in the side panel for easy modification. You can also turn layers on and off in the editor to try variations.
Full release of material layering system will be in 4.20, but an experimental release is in 4.19.
Watch this preview video: