Elements can be copied using the graphical symmetry tool, by defining a reference axis. An immediate preview of the copy is displayed.
CAD Modifications toolbar: click
.
Ribbon > Utilities tab > CAD panel > Plane symmetry dropdown list > Axial Symmetry.
Select an element or a group of elements to copy.
Access the command.
Place the cursor above the element defined as the symmetry reference.
Select a symmetry mode by pressing the <Tab> key while the cursor is placed above the reference object.

Copy elements by axial symmetry
Click when the desired symmetry is obtained.
The copy is created.