Dormers and Roofs

[ds470847]

Is there anyway for me to figure out the proper wall, roof, dormer wall/roof, thicknesses so that there are no overlaps? In other words I want the dormer and roof angle transitions to flow w/o one plane jutting out of another.

[ 01-02-2006, 10:55 PM: Message edited by: ds470847 ]

[islandmon]

Basically, the Roof Procedure modifies a 3D Polygon by the 'Pitch factor' which is the inverse cosine of the pitch angle. For example, a 30? pitch = 1/cos30 = 1.1547, therefore if the plan length of a Rafter is 10 , then the Pitch length is 11.1547. Lets say you what to cut-out a 5x5 opening in the roof surface . Depending on the orientation per XY the opening would then be 5x5.7735. Similar functions using sin determine the height of the dormer wall to match the pitch angle.

[Kevin]

In my experience, this is a matter of trial and error. There are two places to make adjustments. One is in the OIP, and the other is by clicking on the dormer selection handle.

By adjusting roof pitch and thickness and adjusting the offsets from edge of main roof, you should be able to accomplish your task.

I still have to use trial and error as I can never seem to remember how different dimensions affect which direction the dormer, or skylight will move on the main roof.

Just plug in different values and see what happens. You can then fine-tune your positioning until the skylight or dormer is where you want it.

[Travis]

Are you aware that VW will create automatic dormers? Just select a window PIO (Plug-in Object) and insert it into the roof. Your editing options, once inserted in the roof, are somewhat limited so you may end up redoing it a couple of times. But the roof-to-roof geometry will be correct every time.

If the above doesn't produce what you're looking for, I would be "building" the dormer walls on the roof using the Wall PIO and then angling one end of the wall to match the roof pitch. Use the 3D edit tool while viewing the dormer wall in elevation. Then I would "build" the dormer's roof using either the Create Roof tool or by creating the individual Roof Faces.

Since the method of construction of a dormer is to build it over the main roof (commonly called "overbuilt") either before or after the opening is cut out, it might help to think in terms of how it would be constructed. The dormer roof simply butts to the main roof.

Good luck,

[ds470847]

I have a 45 degree hipped roof with 45 degree gabled dormers. In Vectorworks, how do I adjust the dormer wall and roof thicknesses, so that the dormer is flush with the main hip mass. I have played around with the geometry, but it always seems to mismatch. Thank you very much for your reply.

It seems the program itself allows should be placing the dormer flush with the roof. I have determined what thickness a 45 degree hip roof should be to meet with a 7.5 inch thick wall. Still no good however.