Wednesday, June 22, 2016

Profiling Curtain Wall Mullions

What Revit categorizes as curtain wall we use for anything from actual curtain to skin, store front, interior partitions, windows and so much more. It's a very versatile tool. And as versatile as the curtain wall is the mullions we place in them are less so, or so it would seem. 

Revit works like this...

Each mullion type is based on a profile family. The profiles that ship with Revit are system profiles. You'll notice in the type properties of the mullions, the profile is set to either Default or in some cases System Mullion Profile: Rectangular. Corner mullion families don't reference a profile at all. You cannot edit these profiles and there are only a few parameters to adjust them. You can change the profile in the type properties of all mullion types except the corner mullions

(Warning! Corner mullions are not easily reloaded into a project. Take care when purging models to avoid purging corner mullions)

Don't like it? Customize it

The good news is you don't have to settle for the out of the box mullions. There is a Revit family template specifically designed for the creation of mullions. Since mullions are base on profiles, the skies the limit as to the shape you want to create... almost. There are limitations of course, but there's one mullion profile I want to focus on in particular. The mullion used with a butt glazed joint is a popular one and I'm asked all the time how to create it. It's actually not too difficult, but there are definitely some tips and tricks that you have to know to make this one work the way it should.


Read the fine print!

As stated earlier, mullions are just profile lines drawn two dimensionally. Revit does the rest for you. Don't forget to read the little note in the mullion profile family template about where curtain panels are trimmed what a mullion is inserted into the curtain wall. Understanding this makes all the difference. I like to add a dimension parameter to the length of the mullion so it's easy to stretch. You can also add a width dimension parameter to it for even more control. 

Load it up

Load this family into your project and add it to a mullion family. You can either duplicate one of the existing mullion families or right click on the family and choose create new type. Then just switch out the mullion profile in the type properties with the new one you created. 

A few minor adjustments 

Making adjustments to this family isn't exactly straight forward. For example, to adjust it you have to edit the type properties in the mullion family as well as the profile family.

Revit is a Calculator!

I find few people know this little tidbit. Adding an equal sign in front of an expression turns Revit into a calculator. You can use this little trick almost anywhere you have a dimension. That means you don't have to guess what 4.5" + 1 21/64" to adjust the length of this mullion. You can let Revit do the math for you. 
It's 5 53/64" by the way. 

Here's the final curtain wall with butt glazed panels. I hope this was helpful and adds to your work flow. Certainly if you have any questions about how to create your own mullion profile please do not hesitate to ask me. 
Also I'd like to hear from you if you have any other uses for the Revit Calculator. I'd be interested in hearing about any use cases where you found it useful. 

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Welcome to revitED!

RevitED (Revit Education) and general BIM topics. I've been using Revit now for 11 years, and though I feel I've got a pretty good handle on the software it seems each day I learn something new. I want to share that with the readers of this blog and hope you learn something new as well.