Joachim,
I started to investigate your first question about the areas, but it would help a lot if you can send me a pla in mail.
About the zone areas: currently the zone areas does not take care of the wallniche/wallhole commands. The additional areas are calculated by the width of your window, and the depth of the additional area is calculated with the value of Parapet Wall Inset. You’ll find this value in the Details page in GDL Editor, in the Compatibility Options palette, near the Nominal Frame Thickness. Please check the calculations in AC’s standard library, and feel free to ask if you have any additional questions.
Gergely Fehér
Team Leader, Library Team
GRAPHISOFT SE