Hello, Your system has a raft foundation. But I think your question doesn't mean that raft foundation. The expressions RD1 and RD2 in the basement are abbreviations of the word rigid diaphragm. There are two rigid diaphragms (RD1 and RD2) in your basement because there is a stage. You may have thought of these abbreviations as raft bases. You can see the rigid diaphragms from the Analysis mode: The error you get in the report is the results of the in-plane stress control of TBDY Article 7.11.3 for the floors in the RD1 1. rigid diaphragm and the floors in the RD2 2. rigid diaphragm. This control is not provided in the flooring in the specified rigid diaphragm. If the calculation axis of the D101 slab on the basement floor is selected as upper flat + lower flat in both directions and sufficient reinforcement is increased in 2 directions (fi12/18), control is provided.