The primary advantage of the "by story" summary is its direct alignment with seismic code requirements. Most international standards, such as ASCE 7 or Eurocode 8, define lateral loads based on floor levels. By summarizing mass at the story level, ETABS provides a clear snapshot of the for each floor. This allows engineers to verify that the program is correctly calculating the mass source—including self-weight, superimposed dead loads, and the appropriate percentage of live loads—ensuring that the resulting base shear is physically realistic. Efficient Error Detection
Mass moments of inertia; critical for capturing torsional effects. etabs mass summary by story better