Mirror dialog box

Mirrors selected sketch geometry about a selected line.

Access

Ribbon: Sketch tab Pattern panel Mirror

Select

Specifies sketch geometry to mirror.

Mirror Line

Specifies the mirror line about which the sketch geometry is mirrored.

Self Symmetric

Available when the geometry selected to mirror is a spline, and crosses the mirror line. When selected, the mirror command creates a single spline that is symmetric about the mirror line.