I'm getting the following warnings in the output file, version 22.08.00.175:
*** NOTE: NEITHER "MASS" NOR "GRAVITY" REFERENCE LOADTYPE IS PRESENT. MASS MODEL IS FORMED BY COMBINING ALL "DEAD" AND "LIVE" (IF ANY) REFERENCE LOADTYPES. *** NOTE: MASS MODEL FORMED WILL BE USED IN SEISMIC/RESPONSE/TIME HISTORY LOADING, IF ANY. IF MASS MODEL IS SEPARATELY PROVIDED IN INDIVIDUAL LOADING, THE GENERATED MASS WILL BE REPLACED BY THE MASS PROVIDED IN INDIVIDUAL LOADING.
I understood that reference loads being defined as a mass (in Y only) instead of defining loads in all three directions was only possible for seismic load cases in this version of STAAD. Can I define the reference loads as masses in Y only and will the results be valid for 3D time history/steady state analysis?
I would suggest that you define the loading in three orthogonal direction to get rid of any further complicacies. We have come up with a mass model generator and it is very helpful-
https://communities.bentley.com/products/ram-staad/w/structural_analysis_and_design__wiki/58287/how-to-use-mass-model-generator
Is loading in the mass model able to be entered in Y only?