Go to the HELP menu and look at the Archicad YouTube channel.
In there you should find a few movies on the multi-plane roof tool.
That should be a good start if you don't want to read the reference manual.
There is a good section in there on editing roofs but I prefer to see it in action rather than read about it.
Barry.
One of the forum moderators.
Versions 6.5 to 27
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11