To me this is an example of the existing features (schedules) not keeping up with new features (PBC).
But on the other hand it would be a very tricky one to police.
Imagine your wall continued below the slab - the PBC would cut a notch for the slab but where is the bottom of the wall - the slab or the actual base of the wall well below the slab.
Also what if your wall interacted with slabs at different heights - i.e same one wall with a dropped garage floor and a standard height floor at storey level further along.
How would Archicad know what you are referring to as the base of the sill?
Personally I would still construct it with the wall starting at slab level and a second wall below - the PBC can still do its magic on this wall below if needed.
This also helps when placing doors - make them all "sill to wall base" and you will never have a problem with bit of wall across the threshold.
Barry.
One of the forum moderators.
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