Hi Bruce,
Its a shame you didn't subscribe to Infinite Openings after your trial of it 2 years ago, as we have solved this issue. I set this up for Cottee Parker who need it for the same purpose. It works through an MVO setting so it can be actually applied to the documentation type. The result is the removal of all geometry leaving only the wall opening with 3d linework creating a cross.
There have been a lot of improvements since your last trial so maybe you would like another look at the tool.
For anyone else posting problems and shortcomings with windows and doors... the answer is Infinite Openings
https://cadswift.com.au/products/Infinite-Openings.html
Creator of Cadswift's parametric GDL libraries
Creator of Infinite Openings and Component Catalogues
Push the envelope & watch it bend
website:
https://cadswift.com.au/
YouTube:
https://www.youtube.com/user/CADSwift/playlists