Roof extension under itself

[nathaniel.mcmahon]

Trying to extend the lower hanging roof section into the wall under the main roof which involves it going under itself.

I've tried changing the boundary lines but they aren't allowed to cross and I've also tried to join roof to wall whic doesn't work either (because its made from sun elements?

Advice appreciated 

[barthbradley]

Use the Shaft Tool

I misunderstood. Can't you add that section of roof then join the two?  

...you know, I just looked at your rvt and I'm wondering why you didn't just model it as 2 roof and attach them. Seems to be a lot easier -- and the finished look would look better by eliminating all the triangulations being imposed by shade editing.  Plus, it would make it easier to create the dormer wall opening. 

[nathaniel.mcmahon]

It's currently all one roof

[constantin.stroescu]

Use Join Roof function even if you have a single roof:

• select Join Roof
• pick the Edge -1 
• pick the Wall face

[constantin.stroescu]

you can see it more clearly in this screencast:

https://knowledge.autodesk.com/community/screencast/755ab880-2a50-42a4-b872-a3d75d06ef4c

[ToanDN]

I actually didn't know a roof could extend to a wall using Roof Join tool. Thanks for sharing!

[nathaniel.mcmahon]

My roof is a bit more complicated than yours hence why that solution doesn't work. I've had to construct it using sub elements and apex line to get different eave heights with one single apex.  

[ToanDN]

See attached.