Thanks Nick. That got my test Icon appearing in red, but the 3D one now doesn’t render because its translucent. Is that because its experimental or is there something else I’ve missed?
No but it shouldn’t need to be - the OP has made several errors, UI materials are not ‘Lit’ to start with - so the lighting option should be ‘Unlit’ instead of ‘Default Lit’, at which point BaseColor, Specular etc all go gray and Emissive is the only one available.
In 4.10 and above, there is a new material domain called ‘User Interface’ which will change all of the material output nodes to other things anyway (Emissive becomes FinalColour for example). Any materials you’re using in the UI should be set to that Material Domain, UMG will warn you if you don’t now anyway.
The base color does not get changed to FinalColor. You will get no output if you have your material using BaseColor, regardless if your domain is UI. So, since it’s not documented, people are just left to pulling their hair out wondering why nothing is showing up.
If you try to use the material on a UI element, UMG will throw an error telling you the material is not set to the correct domain.
‘Emissive’ get’s changed to Final Colour, not Base Colour. This is just a terminology misunderstanding, ‘BaseColour’ is one of the components for lighting / PBR. For an unlit material it wouldn’t make any sense.