Intersecting Roofs

Taking a break from news and design to share some techniques for roof making in Revit.

In northern climates roofs are often steeply pitched to shed snow.  Many structures in New England have collapsed because they failed to follow that simple move.   In this post I'll explore some methods to create this particular pitched roof condition:

One method is to create two roofs and join them.

Joined Roofs

First create a footprint roof.

Next create an extrusion roof choosing a vertical workplane. In the example below the pitch is the same as the main roof and the bottom of the roof sketch starts at the top of the main roof eave soffit.

Once the extrusion roof is created you can adjust its start and end points and use the Join/Unjoin Roof  tool to attach the far end of the extrusion to the face of the main roof.

There are a couple issues with this setup.

1. The main roof is still present under intersecting roof. If the roof is not made from trusses you must use the Dormer Opening tool or an in-place void family to cut it out.
2. If you want the fascia of the intersecting roof to be aligned with fascia of the main roof you will see the following error when you attempt to align them:

Revit doesn't like this condition yet there are always alternatives...

Roof Shape Editing

Below I deleted the intersecting roof, removed the slope arrows from the main roof, and used the shape editing tools to Add Split Lines as my ridge lines.  The Modify Sub Elements tool can then move points up to the desired height.

Roof Slope Arrows

Last I'll share a rather obscure and old way of achieving this roof that might help you win a revit knowlege contest at AU next season.

In this scenario you make a roof sketch with 3 lines on the south boundary - two slope defining and one not.  Next over the non-slope line draw two slope arrows that point to each other.  For accuracy I drew one slope line, set the properties for its head and tail, then mirrored it to create its twin.

The fasicas are aligned, the space under the perpendicular roof is open and all with one sketch!

I'm certain there are other ways to acheive this condition.  Feel free to share or point out other posts on the net.

_erik

Comments

[Chad Clary]

In the first part, why would you draw your roof as an extrusion instead of a standard roof object with pitches in plan?

[Anthony Hauck]

Sure.  That would work as well.  You can sketch a small footprint roof with two slope defining lines.  This would work as long as the slope is constant like the example.

[Landhall]

Erik, do you have a small bucket of tips and tricks for showing a new opening in an existing wall when the wall is phase[existing], but the opening happens in phase[new]. How can the new opening be visible in the phase[new]with phasefilter[show demo and new]. Specific useful situation: showing location and size for a new opening in a masonry wall in the demo drawings and not just in the architectural drawings. thanks.

[Anthony Hauck]

Ill look to see if I or anyone here has some tips for this condition.  I would also suggest a post to AUGI which is a fantastic community of Revit experts.

[Christina Huerta]

We developed a little Revit API called BuildEdge Roof - It performs the roof geometry and layout for pitched roofs in a matter of minutes versus hours.

Erik, would you be willing to review it? There's a free trial download on our store, but we could arrange a full version if you're interested in checking it out.

Thanks for your consideration, Christina
www.buildedge.com