If you are not satisfied with the building masses generated by the program, you may add building masses as line loads, area loads, or point loads. These loads may be negative in order to diminish or negate completely a portion of the generated building masses, as when placing an opening in the floor area. Positive masses can be used to model surcharge loads such as a heavy ceramic floor in one room, or to model mechanical installations and assemblies that the program does not handle.
You must regenerate seismic loads after creating these new masses. If is recommended to check the Generate Loads Only, box if you do so.