: It helps identify if Superimposed Dead Loads (SDL) on null areas are failing to transfer to the seismic mass because a diaphragm wasn't assigned. How to Access the Report To get this better view of your structure’s data: Navigate to the Display menu. Select Show Tables . Go to Output > Other Output Items > Mass Summary by Story . Pro-Tip: The "Mass Source" Secret
A better approach involves two distinct definitions: etabs mass summary by story better
Here’s a professional, engaging post you can use on LinkedIn, a blog, or an engineering forum like Eng-Tips. : It helps identify if Superimposed Dead Loads
Mention if manual meshing was used for walls and slabs, as auto-meshing can sometimes lead to lumping errors CSI Knowledge Base Diaphragm Check: Confirm that Rigid Diaphragms Go to Output > Other Output Items > Mass Summary by Story
💡 Always compare the Total Mass in the summary table to the Base Reaction for a dead load case. They should be identical. If they aren't, your mass source is likely missing a specific load pattern.