This is a wish many have made - not saying it is a bad wish.
As you wrote the plan view is a basically a top view of a 3D object.
This is not quite the case in Archicad.
The plan view is a symbolic top view, not an actual top view.
However, try this.
In you plan, right mouse click and choose "New 3D Document From Floor Plan".
Is this closer to what you want?
You can adjust the 3D Document settings to eliminate the colours and just have lines.
I am not saying it will be perfect, but give it a go.
One of the forum moderators.
Versions 6.5 to 25
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