Thanks Wes
I have played around with a few methods and the fit walls to roof seems to be the best option.
My next question would be, how do I remove all the hip roof information inside and out of the dormer. I don't want to use the subtract solid option because I want to maintain the editable aspect of the roof symbol. I have tried to create a skylight cut out by making a 3D symbol the size and shape of the hole but when I click the "do not insert object" option, I dont get a hole. Nothing is there, but the dormer option are.i have tried flipping and changing the object in edit mode but not change.
I attached an image.
thanks
Chris