Custom window - hole not the same shape as the window

[DangCad1]

I have created a custom window using slabs (File > Libraries and objects > Save Selection as > Window) (see screen 1)

The window turns out like I want it to - however, the window hole is rectangular, instead of being the same shape of the window. See screen 2 with settings for the window, can't find anywhere to change this. What did I miss in the process?

[a2o-architecten · Accepted solution]

Did you use a extra Slab or Roof tool to create another element whose contour matches the outer contour of the desired wall hole or wall niche? The element ID field should also be named to 'Wallhole'.

Try following workflow: https://help.Graphisoft.com/AC/25/INT/index.htm?rhcsh=1&rhnewwnd=0#t=_AC25_Help%2F040_ElementsVB%2F0...