Here is a link to a post with a few different options.
This should help.
http://archicad-talk.graphisoft.com/viewtopic.php?t=22847&postdays=0&postorder=asc&highlight=roof&&s...
Basically you want a roof plane that slopes in 2 directions.
And then mirror for the second side and trim together.
The easiest way is to define the roof in the 3D window.
Barry.
One of the forum moderators.
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