You can place a new single roof plane in the 3D window using the 3 blue circle nodes as the first three points of the roof.
This will define the slope and pivot line - then you define the other nodes of the roof plan which of course you can edit as you like.
Just be aware the first 3 points you pick will define the underside surface of the roof - not the top surface.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11