split level

[poelcat]

It has become obvious that no one has any input to assist me in this problem since there have been 65 views and only one reply. Lew's reply is good but does not address the real problem of Chief i recognizing a negative floor level.

[Glenn Woodward]

OK, OK, I'll bite.

I don't quite understand your problem as Chief WILL recognise a negative floor level.
The problem could arise where you do not have the room to place the floor with a negative floor level because you already have a floor drawn there. ie, you can't have 2 floor levels occupying the same place on the same floor plan.
In which case, you need to follow Lew's advice.