1.Open the assembly containing the assembly feature to mirror.
2.Click Assembly Features (Assembly tab on the Command Manager) and click Mirror , or click Insert > Assembly Feature > Mirror.
3.In the Property Manager: For Mirror Face/Plane, select a plane or planar face to mirror about.
The Mirror Part feature can be used to create a mirrored part, which is just what the name implies, the opposite-hand version of an existing part. Mirroring can be done on either a model face or plane.
In assemblies, when you mirror a component, you can create an opposite-hand version of it, positioned symmetrically about a plane. You can edit mirror component features to add or delete components and make other changes.