This option defines self-weight loads acting in a particular direction for structure elements. Open the Self-weight dialog by clicking in the Load Definition dialog.
You can define the direction (direction of one of the global axis X, Y, or Z of the coordinate system) of the load caused by self-weight in this dialog. When Opposite to axis sense is selected, the sense (orientation) of the self-weight load is opposite to the orientation of the selected axis of the global coordinate system.
Notice that after body loads are defined, added masses are not considered when generating bar weight. In addition, you can define an increment factor for a self-weight load record. This is used for example, when the equipment on a structure is not modeled accurately in a calculation model, but is accounted for by implementing a self-weight increment factor. You can define the factor in a table for the self-weight load record and in the previous dialog.
See also:
Comments concerning automatic assigning of a self-weight load to the whole structure