This geometrical operation allows to perform a symmetrical copy of your mesh or some of its elements.
To apply symmetry to your mesh:
From the Modification choose Transformation and from its sub-menu select the Symmetry item. The following dialog box shall appear:
This operation has three options, you can symmetrically copy your mesh or some of its elements specifying:
one point
one axis (point and vector)
one plane (point and normal)
Toggle the corresponding checkbox to Select whole mesh, submesh or group.
When Move elements radio button is selected, the source mesh (or elements) is created at the new location and erased from its previous location.
When Copy elements radio button is selected, the source mesh (or elements) is created at the new location, but it also remains at its previous location and is considered one and single mesh with the result of the translation.
When Create as new mesh radio button is selected, the source mesh (or elements) remains at its previous location, and a new mesh is created at the new location and appears in the Object browser with the default name MeshName_mirrored (you can change this name in the adjacent box).
Copy Groups checkbox allows copying the groups of elements of the source mesh to the newly created one.
See Also a sample TUI Script of a Symmetry operation.