Thanks, but I would absolutely not want to explode all “blocks” to individual layers, because that would mean ruining the object hierarchy, and also, 100s of flat layers would be impossible to manage.
I specifically want to select a sub-assy. I can see it in the BlockEdit that the thread you posted told me about, and I can select the sub-assy in that dialog, and see it highlighted in the viewport. But I can’t seem to retain the selection in order to move it or place it in a separate layer.
Why isn’t BlockEdit a panel like the Layers panel?
EDIT: When selecting a sub-assy with the Block Editor open, I then selected it again in the viewport and hid it. I then pressed OK and was greeted with these two popups:
So, it seems that Rhino understand hierarchies, but that’s as far as it goes. You can’t work with them, because the user experience just isn’t there for it. That’s fine, for the price tag of Rhino. Crossing my fingers to see this improved in V7.