Mirroring in three dimensions

You can create a mirror image of selected entities in three-dimensional space. You mirror the entities about a mirror plane that you define by either specifying three points; selecting an existing two-dimensional planar entity; aligning the plane parallel to the xy, yz, or xz plane of the current UCS; or aligning the plane with the current view. You can delete or retain the original entities.

To mirror an entity about a three-dimensional plane

Do one of the following:

Choose Modify > 3D Mirror.
On the Modify toolbar, click the 3D Mirror tool ().
Type mirror3D and then press Enter.

Select the entities, and then press Enter.
In the prompt box, choose 3 Points, or press Enter to select the default.
Specify the first point on the mirror plane.
Specify the second and third points on the plane.
In the prompt box, choose one of the following:

Yes-Delete Entities to delete the original entities.
No-Keep Entities to retain the original entities.

Select the entity to mirror (A), and then specify the first point (B), second point (C), and third point (D) defining the mirror plane.

The resulting mirrored entity.

How do I...

Mirror entities