Try setting the walls as well as the doors and windows to 'Symbolic'.
I try to avoid using the FPCP when ever possible because you not only have to set a level (often one level does not suit everything) and you have to be careful about the extents to which you can see.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11