How to cut a roof on a roof

[Anonymous]

I need to put a small roof on another roof like on the picture. I was able to cut the bigger roof but I dont know how to cut the extent of the smaller roof that goes inside.

[barthbradley · Accepted solution]

If you are able to create the two roofs separately - and join one to the other using the Join Roof tool - then you can use the Dormer Opening tool to create the opening in the lower roof. 

,,,or you could do it all in one Roof Sketch using Slope Arrows.

....with two Roofs and Dormer Opening:

Join Roofs | Revit 2020 | Autodesk Knowledge Network

[mauricio_mssf · Accepted solution]

How to cut a roof on a roof  See the Screencast how I do this union.