Demolish existing roof with new dormer in new construction

[mirceaatbowtie]

Hello people,

I am having an issue here with an existing roof which we want to demolish partially to create a new dormer. I have attached 3 pictures showing existing, demolished and proposed. 

So I tried the dormer command and "Pick Roof / Wall edges " but I get this error:

"Dormer Opening Cut is not fully defined. Cut was not performed."

Tried cut by face and vertical and I think it will cut through the existing roof in the existing phase rather than demolishing a part of the roof in the new construction phase. I suspect that because I get an error also that the Rooflight is losing its host.

So I guess my question is:

- can I demolish a part only of an existing roof in new construction ? also it would be nice if it could infill automatically the bit on the left hand side where the old dormer was - similar to what walls do when you demolish a window.

or 

- do I have to demolish the whole roof, build a new one which only has an opening for the new dormer ?

Cheers.  

[barthbradley]

Why don't you not use the Dormer Tool at all, and just model the Dormer infill portion as an independent and phased Roof?

[RDAOU · Accepted solution]

@mirceaatbowtie 

• If you use Opening tools, auto infill is not an option...for Auto-Infill you will need to use an Insert Family to cut with instead of dormer
• Opening tools (By Face/Vertical/Dormer) inherit the Phase of the element they are cutting...ie: they will be existing Phase and you will not be able to quantify the demo of the roof)

As it is now in the images you posted, it works as follows

1. Demolish old dormer in New Construction
2. The Existing dormer opening you leave be as is
3. You model the new walls and roof in new construction
4. Use either an in-place void or a face Generic Model void to open the Existing Roof for the new Dormer (If you want to quantify the demolished part of the roof)
   • Otherwise use opening by face and trace the new opening using new Walls/New Roof/The old Dormer opening
5. Fill in the Gaps/patch with a new roof to match existing

           

[ToanDN]

Those (Vertical Opening Cut, Opening by Face, Dormer, Wall Opening) are geometry modifier tools, they are not phase-able.  You can do one of the following:

- create a family or in-place family with a void or an opening under New phase and cut geometry the existing roof with this family (while you are in the family editing environment)

- Split the existing roof into two and demolish one

[mirceaatbowtie]

Excellent stuff. Thank you very much