Interesting topic. I have nothing to contribute since i don't use key plans. But hear me out.
Don't the grid lines fulfill the same function to show where a view (that is only part of a building) is located? As long as there is a complete building view with the grid lines, that technically should provide the same information and every other view of parts of the building can be located.
That likely isn't possible, but a key plan that automatically highlights the shape of the view would be nice. Like if you look at above area plan by ToanDN, if your view of area A has that shape, the area plan should highlight the exact same outline automatically and should change if the shape of that view gets changed. Probably not possible for normal users.
I guess I never liked them since it seems it inherently isn't an automated process. but don't let me distract you if you think they are useful. If there is a great idea to do them, I'm open to re-consider.
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