Thanks for clarifying, Yossi, I scanned that too quickly and understood it as being equivalent to the same drop-down in mxed, which allows changing a material’s type at any time, with the UI changing to show params for the currently-chosen type.
Andreas, after previous conversations along these lines, I began exploration for a new feature on the core materials, which will appear as a stack of materials, to overlay the current material. It’s a bit tricky, since those materials then also have the same stack, and so forth, but it looks doable, and can be done in a quite simple way, with each item in the stack just consisting of a material & opacity pair (with opacity controlled by scalar percentage or texture).
Regarding node systems, the main reasons people use them — whether or not they are represented that way to the user — are just that they represent good software design (breaking functionality out into small, independent units, each with minimal knowledge of the world outside it), and provide powerful extensibility. I agree they are not very user-friendly, and have avoided creating a 2D node graph yet in bella (though this would be a fun type of development), in order to force myself to come up with user-friendly ways of dealing with them. Adding such a graph surface can tend to be used to shift all responsibility onto the user.