A bit addition to my previous post:
I just realized that the Railing Reference Line can be a curve as well in the Floor Plan so it is possible to model this out of a single Railing segment. You can model the Railing in a horizontal plane, then you can just raise the endpoint of the Railing Reference Line to the desired height.
The Morph method is also feasible. However, I prefer the Railing method because its Top Rail can be parametrically modified to use a different Profile, while in the case of the Morph you would have to remodel it. Also, the Railing tool offers more flexibility and options for achieving the desired Floor Plan representation.
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