Switch Mtl respecting mtl overrrides

[ricoholmes]

While VRayShaders are always used here for rendering, they often (currently) just don't give enough visual feedback in the viewport*. For clarity, we almost always use a Lambert or Blinn for viewport interaction with MaterialOverride for renders.

firstly: Material Switcher is just fantastic, thank you.
When dropping a preview lambert into a slot however, it doesn't represent in the viewport ( we just get the green "SG Unassigned" vp shader).



It renders perfectly fine I must add- properly respecting the VrayMtlOverride

*Triplanar being the main cuplrit atm
It's your own fault, really. You shouldn't have made Triplanar so brilliant and indispensable

[yolov]

With 3.40.02 and later we have improved support for materials representations in the viewport. For layered materials and ones such as the switchMtl you need to enable the textured view to see the material connected to it.
The downside is that it will work for only the first material from the list, we can't really do much more than that for the moment, since the things done by the SwitchMtl happen at render time. That goes for other materials like the wrapper, bump and so on.
This works with Viewport 2.0 and with the new OpenGL display modes for it (introduced with Maya 2016 and later), i.e. Core Compatibility and Core Strict. The "Legacy" OpenGL mode uses our old code where most of those things don't work that well.
The other downside is that V-Ray lights still don't illuminate the objects in viewport 2.0 (with the new OpenGL modes) but we're working on it.
Actually the new OpenGL modes gave us the ability to do that.
That would be the way to see something better than the unassigned representation.
Also a lot of textures should work better now, e.g. plugged into anisotropy, reflection, glossiness and so on (with the exception of bump and the V-Ray procedural textures). Regraction is represented as transparency for the moment, but that's a limitation we can't get around.