Mirror
To mirror selected objects on a plane, use the menu item
- Edit → Mirror,
the shortcut menu of the object, or the corresponding toolbar button.
The following dialog box appears.
To keep the original object, select the Create copy check box.
The Mirroring Plane can be defined in two ways:
- The mirroring plane runs parallel to a plane that is defined by the axes of the global axis system XYZ. In this case, activate the first option and select the relevant plane from the list. Then, in the Mirroring Plane dialog section, enter a point that lies in this plane.
- The mirroring plane lies anywhere in the work plane. In this case, activate the second option. Then, in the Mirroring Plane dialog section, enter three points that define the plane.
If a copy is created, you can influence the numbering of the new objects in the Numbering Increment for dialog section.
Use the 
button to open another dialog box with useful options that are described in Chapter 11.4.1.