Considering the drawing to be an assembly, AutoCAD Mechanical toolset enables you to set the properties for the entire assembly in the BOM.
If the drawing is a part drawing, you can use assembly properties to specify the component properties of the part.
Title blocks created using the AMTITLE command can retrieve and use assembly property information, without requiring you to key them in again.
When you create an xref to a drawing, in the BOM, the xref drawing is considered a part or assembly. The assembly properties that have been set in the xref drawing are displayed in the BOM of the host drawing.