M. To use starting vectors with load-dependent Ritz vectors

You must set the eigen method to use load-dependent Ritz (LDR) vectors in order to specify the starting vectors for that method. On the Analysis and Design ribbon tab, select the Miscellaneous Commands > Set Eigen Method tool in the Analysis Data group. Then select the Load Dependent Ritz Vectors (LDR) option and click OK.

Note: This method is used to specify starting mass loads only. In order to specify starting load from reference load cases, you must directly edit the STAAD input file.

Select the Loading page in the Analytical Model workflow.
Select Starting Load Definition under Definitions in the Load & Definition dialog and then click Add. The Add New Define Starting Mass Load dialog opens.
Select the directions you want to use for the starting mass load vectors.
(Optional) For each direction selected, enter the number of vectors to be extracted corresponding to that load.
Click OK.