While it is not recommended, you can add or delete members using the spreadsheet and the Update STR Model from Spreadsheet command. For example, you can copy a steel beam that exists in the spreadsheet, paste it into a blank row, and then change its location X, Y, and Z points. Then update the STR model, and the member will appear in the model itself. If you delete a row from the spreadsheet and then update the STR model, the member will be deleted in the model.