This dialog is accessed by clicking the 
Justification Settings while the Duct tool is selected. You can specify the following justification layout options.
- Horizontal Justification: aligns the edges of duct sections horizontally, using the Center, Left, or Right side of the duct as a reference.
- Horizontal Offset: specifies an offset between where you click in the drawing area and where the duct is drawn. This option is helpful when placing ductwork at a fixed distance from another component in a view.
- Vertical Justification: aligns the edges of duct sections vertically, using the Middle, Bottom, or Top of the duct as a reference.