How to select only bottom face of a ceiling or floor?

[jacob.small]

As was noted above, this is a common question and answers can be found via search. One such example (for top faces instead of bottom - you’ll have to change a bit of formulas):

Get top face of an element

Hi, the damn special case, although in the question one can suspect the top face of the element (mandatory double filtering to eliminate in the case of inclined beams) [image] cordially christian.stan