#Mirror a body

Key M. Select the body, click the mirror plane, datum plane or face in the viewport, press Enter. The With the original (union) tick keeps the source half and merges the reflection with it into one body; without it only the reflection stays.

#Half the work instead of the whole

A symmetric part is drawn as one half and mirrored. The gain is not only time: a change to one half carries over by itself, because the other half is not a copy but a consequence.

#What serves as the mirror

A base plane, a datum plane or a planar face of the part itself. A datum is handier: its position is parametric, and the mirror can be moved without touching the body.

#A hint

If the part is symmetric about the origin, draw it so that the plane of symmetry coincides with a base plane: then the mirror needs neither a datum nor dimensions.