Use the Mirror tool to mirror/reflect selected entities
across a symmetry plane.
You may reflect input or keep input and reflect duplicate instances of the input.
From the Geometry ribbon, click the arrow next to the
Edit tool set, then select Mirror.
Optional: On the guide bar, click to adjust the stitching
tolerance.
Choose an entity type using the selector on the guide bar.
Select the entities to mirror.
On the guide bar, click
Plane.
A preview of the mirror of the selected entities will be visible in red. The
displayed preview is based on what entities are selected and how you position
the mirror plane.
Position the plane using the Vector tool.
On the guide bar, click Mirror.
Merge two coincident faces by selecting faces with window selection and then use
the Mirror tool. This technique works well with mirrored
entities.