How to extract windows "opening cut" in order to add dimensions to windows in elevation?

[jacob.small]

I was thinking the use of the nodes shown here:

Reference from FamilyInstance

A great example in python by @lucamanzoni or @Ewan_Opie will probably be more appropriate if you want to understand how to do it, but if you are in a hurry, there are already custom nodes. [FamilyInstance%20Reference]