Hello, If your ground layers, the part you specified as the fill, starts from the top of the 1st basement floor, your definition seems appropriate. If you press F1 on the keyboard while the ground layers dialog is open, you can get help on the subject. Values appear as default in layers. In a structure with DTS=1 and BYS= 6, to solve limited ductility, you must meet the 75% shear overturning moment condition in both directions. Some notes: -You have given the P07 and P09 curtains an upper level on the 1st basement floor. In order for the group curtain elevations to be the same in the floor, it would be appropriate to enter P08 by giving the elevation. -Your K18 and K22 beams are not connected to the curtain group. This is because the axis intersections are not used when defining the curtain group curtains, and the offset difference that appears when you zoom between the curtain corner notes and the beam node points occurs. When the deformations are examined on the 3D screen, you can see that the elements are not connected. -The tooth spacing in your project does not seem to be compatible with the desired tooth spacing in bidirectional gear slabs according to TS500 11.5. I suggest you to review TS500 clause 11.5 and related 11.3. - If you want to solve your stairs together with the building, it would be appropriate to use the semi-rigid diaphragm option since you have stairs connected to the floor. -There are shear force jumps in your columns due to your floors at different elevations. You can arrange your element and floor elevations to be 0.01 cm, or you can consider the solution option by saying creating a rigid diaphragm from the properties of floors at 16 cm elevation. Good work