This is a series of old-fashioned extrusions modelled in-place. I chose the Mechanical Equipment category because I'm not expecting to use this later. This provides a simple way to isolate or hide this second massing model in different views.
Now I have a pretty good grasp of the 3 dimensional form and incidentally the model that comes up in Google 3d buildings is very misleading in this regard. I wonder who vets these models. Did anyone think of approaching SOM ? My next goal was to quickly flesh the massing model out with curtain walls & floors.
The horizontal mullions are unevenly spaced with 2 small opaque spandrels below each clear glass panel. You can't create this directly from the dialogue box. It would be possible to add in extra grid lines, then select rows of panels and change their type, but this is tedious. Instead I made a custom panel with embedded "transoms". This worked like a treat and was easily adpated to make a second panel family for the first floor glazing.
A third panel family has 4 equal panes of opaque material. Tab-select a single panel, right-click/select horizontal row, unpin (wait for this to take effect) and change the panel type in the type selector. For the plant room louvres I made a sub-type of the original family and changed the glass material to "louvres". The material uses a horizontal fill pattern in shaded views and a cut-out for rendering. You can go to the trouble of making fully 3 dimensional louvres if you like, but it's a lot of effort for little gain and will slow your model down.
I don't think I have the mullion spacing 100 percent correct yet, but it renders up quite convincingly. Would be more life-like with some internal lighting and blinds pulled down to various different heights. But that will have to be another weekend.
For now I will finish with a couple more renders. If you look carefully at the last one you will see a vertical mullion near the corner that shouldn't be there. But remember, my goal is to use Revit as a research tool. Success is not judged by the perfection of the model, but by the learning process it enables.