Good work, The operations are given in the pictures respectively and presented to you with the project file. 1. First, create your slab flooring. (Slab thickness as 12cm) 2. Turn your flooring into ribs. ( After completing this process, the slab thickness will remain 12 cm and the rib beam height in the rib settings will be 35 cm.) 3. When taking sections; For sections parallel to the rib beams, pass the section line not through the rib beam, but where the hollow brick is located.