I'm new to the program so forgive my ignorance. However, without defining a new floor, I could not define the floor that fits on the basement curtains. I tried to explain my problem with the attached pictures, I would be glad if you could help. Scenario The building should consist of a single ground floor. Let the floor height be 3 m. Let the floor level of the ground floor or the upper level of the basement be 0.00. Even if the lower level of the basement walls is not important, let it be -0.80 m and therefore the upper level of the foundation should be -0.80 m. My question; How can we define flooring without opening a new floor (basement floor) to the 0.00 level or the upper level of the basement curtains. If I could not identify this flooring. While the program is trying to define this floor, it always sees the area covered by the foundation beams (picture 5), not the area covered by the basement curtains. Thanks in advance.