To answer my own question:

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Are there any examples of how to add an App::PropertyMaterialList property to a feature Python object? vobj.addProperty("App::PropertyMaterialList", "ShapeAppearance", "Layer", "tip") Creates an empty list without a Material object (ShapeAppearance can then no...

Try using Part_Builder to 1st create a shell from the faces, and then a solid from the shell.

I have unpinned this topic.

Check the position of the WallTrace sketches.

Most:
X = 1683,08 mm
Y = -1000,48 mm
Z = 2991,92 mm

WallTrace005:
X = 10,00 m
Y = 0 mm
Z = 3000,00 mm

It seems that you are not fully aware of the position of the working plane. Or is the Z of 2991,92 mm deliberate?

From the description I conclude that the contour of the pocket sketch matches the area you want to preserve. But you should create the contour of what you want to remove. The bigger question is: why do you create a pattern (not sure if you have used a linear pattern, but I hope so) of a rectangular ...

@intufreecad Off topic: which software do you use to add the texts and the circled numbers to your images?

The Hosting solution that has been adopted for Arch_Windows is not recognized when exporting. Windows and doors have to be selected separately.

The WPProxy is in the way. If you make it invisible snapping to the arc works fine.

To change your start up WB: https://wiki.freecad.org/Preferences_Editor#Workbenches