Multi-material samples please

[evilC]

I presume 3MF supports the following scenario:

• In CAD editor, I create a model which contains 3 bodies - Parent, A and B, such that A and B are embedded in the parent
  
• Again in the CAD editor, I assign one material (M1) to the parent body, and another material (M2) to A and B
  ie the intention is that A and B are printed in a different colour to the parent body
• Export as 3MF
• Import into slicer
• The important thing here is that the user should only have to make TWO selections - ie pick which materials (eg colour of filament) to use for M1 and M2 - they should not have to make 3 selections (Assign filament 1 to parent, assign filament 2 to A and also assign filament 2 to B)

The reason being that there could be HUNDREDS of bodies - for example, a parent body with hundreds of characters of text embedded into it, but if only two materials were specified in the CAD application (One for the parent body, one for all the characters of text), then this could be a very laborious task

A look at the 3MF spec seems to indicate that this is indeed supported by 3MF via basematerials

I am due to be getting an IDEX printer in December, and will face exactly this scenario, so I am trying to work out how various slicers would handle this. To that end, it would be nice to have a sample file with multiple basematerials defined