Hi there,

You'll want the data table that relates to the wall host. It may be possible in Dynamo to find and connect that table, as Dave says. In this BIMLink example we use the Host wall data for the Mark as well as the wall orientation to assist in the numbering of the mullions themselves.
BIMLink and Reporting on Mullions

We've worked with a number of people on this kind of challenge, and I would not recommend trying to do it manually - it's too difficult to ensure selection.

Automated? probably a job for Dynamo. The way I do it is with a Shared text parameter assigned to the Curtain Wall Mullion category for Floor or CW Mark then I filter all cw mullions on a floor and manually enter the floor number. For curtain wall marks, select the whole curtain wall, filter for cw mullions and manually enter the mark. I have gotten into the habit of saving selection sets of these types of things so to filter for them is very quick and that makes the manual process pretty quick and painless...

Sorry, I should have clarified, you and I have already discussed how to get the right length through formulas, my problem at this point is just trying to get a mullion to report its location, either by level or by curtainwall mark number.

The goal I'm looking for is to be able to provide material take off by floor. I can do it with generic models (formed aluminum, clip angles, etc.) but can't seem to get mullions to schedule in a way that can be checked by location.

Thanks again for all the help Dave!

sigh, what you want to do is certainly possible but it is a bit of a convoluted process since Revit makes curtain mullions in small segment lengths cut at each perpendicular mullion grid location so you need to figure out how to "add them together". Rather than try to explain to you how to do this I've got a PDF doc around here somewhere that explains the process. I'll dig it up before I leave tonight.

As to marking, I've set up my own parameters for this purpose but Revit has OOTB type parameters for curtain wall mullions that you can use if that's easier for you. There's Model, Manufacturer, Type Mark among others.

Edit: well it turns out that the PDF tutorial for scheduling curtain wall mullions is copyrighted and as such I can't share it without the permission of the author. I doubt that that permission would be given looking at the amount of work that went into the 28 page document. Two options, one, you could contact the author and see if he'd share the doc. Might cost you a couple of bucks but the time you're going to save figuring this out from scratch would maybe make it worthwhile. Author is Alfredo Medina at Planta1dotcom. Option two would be for me to try to summarize the contents enough to get you going in the right direction. Frankly, I vote for option #1 and if that fails we go to plan #2.