https://communities.bentley.com/products/ram-staad/f/ram-staad-forum/247721/why-i-am-getting-these-errors-error-no-unsupported-masses-entered---check-densities-errors-in-solver-please-can-anyone-help-meINPUT WIDTH 79 UNIT METER KN JOINT COORDINATES 1 0 0 0; 2 3.00001 0 0; 3 6.00001 0 0; 4 9.00002 0 0; 5 12 0 0; 6 0 3.00001 0; 7 3.00001 3.00001 0; 8 6.00001 3.00001 0; 9 9.00002 3.00001 0; 10 12 3.00001 0; 11 0 6.00001 0; 12 3.00001 6.00001 0; 13 6.00001en-USTelligent Community 12https://communities.bentley.com/thread/773756?ContentTypeID=1Mon, 17 Jul 2023 06:13:02 GMT6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:901ba091-7200-41b2-b10d-f252955fde1aAbhisek M<p><img style="max-height:240px;max-width:320px;" src="/resized-image/__size/640x480/__key/communityserver-discussions-components-files/5932/pastedimage1689574482679v1.png" alt=" " /></p> <p>In the above marked response spectrum load case no mass is defined. You need to define load in 3 directions under this load case to run the file.</p> <p>Alternatively you can use mass modeler to defrine mass reference load case which will serve the purpose for both static seismic and response spectrum load cases.</p> <p>&nbsp;<a href="https://communities.bentley.com/products/ram-staad/w/structural_analysis_and_design__wiki/58287/how-to-use-mass-model-generator">How to use Mass model Generator</a>&nbsp;</p><div style="clear:both;"></div>