Trimming vaulted dormers

[Photi]

Hi.  I'm very new to Revit...only a couple of months...so I only know the very basics.  Can someone tell me how to trim the bottom end portions of an arched eyebrow dormer that extend below the main roof rafters and project into the interior space.  There are no side walls to the barrel vault, so I can't do the attatched Top/Base command.  It's just a truncated shallow barrel vault that sits atop a pitched 12/12 wood framed roof.  The vault itself is based on 2x8's and I used roof extrusion to create the eybrow, then adjusted the length so that the front face and rear endpoints intersect the main roof to achieve the desired shallow barrel height and length.  It looks perfect from the outside, but in section one can see half of the vault protruding into the room below the bottom of the main rafters.  Join roofs doesn't work, nor join geometry, and I don't know how to trim back the vault to be flush with the underside of the main roof rafters.  Think of an arc shape who's ends protrude down below the roof.

Thanks,

Photi

[arunag]

You can try this:

1. First go to modify tab --Join geometry --select the dormer & Main roof

2. Go site plan so that you can see the roof from top---change to wireframe mode---select the dormer roof( I presume you would have used roof by extrusion for the vaulted dormer)

3. Choose the verical opening option ----& select the shape shown in the image(along the arc that you can now see & select)

4. This will cut off the prodtruding part of the dormer.

5. Next you can use the opening by face too under openings---select the main roof--& select the shape of the opening in 3Dview under wireframe to cut off the main roof in the shape of the dormer.

PS: Make sure you select only the dormer roof for vertical opening.