Dimension Curtain wall Mullions

Is there a way to dimension the mullions of a curtain wall?
I know that you can get grid reference from the curtain wall but the goal is to dimension the mullions instead of the curtain wall grid(what I am trying to achieve: Picture below)

So far I have tried to get the faces references of the mullion but somehow element.faces is not working.

Any ideas/workarounds?

Thank you in advance

Did you manage to solve this?

It’s not possible to make dimensions of the mullion,the nodes requires two different element.Thus if you select the curtain wall and get the mullion location and shape,with that location and shape to create tiny detail line,then use these detail lines to make dimensions,here is the video of how I make dimensions of grids,the method is same,the difference is to create more short and unvisible detail lines.
https://youtu.be/A_Pb9WMhe-k