Achille, I voted essential.
James, yes, that Label is a start but it is not the full solution to this case. For example it does not have the Level Elevation marker, and also it can display the top and bottom of the full structure only, but not the top or bottom of the core. I can imagine that this Label could be made smart enough to do all those things, including the Marker when labeling Slabs, Roofs, Shells etc.
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