7 This geometrical operation allows to perform a symmetrical copy of your mesh or some of its elements.
9 **To create a symmetrical copy:**
11 #. From the **Modification** menu choose **Transformation** -> **Symmetry** item or click **"Symmetry"** button in the toolbar.
13 .. image:: ../images/symmetry.png
19 One of the following dialogs will appear:
21 It is possible to mirror a mesh or some of its elements through:
23 .. image:: ../images/symmetry1.png
29 .. image:: ../images/symmetry2.png
35 .. image:: ../images/symmetry3.png
39 a plane (defined by a point and a normal to the plane)"
45 * specify the elements for the symmetry operation:
47 * **Select the whole mesh, submesh or group** activating this checkbox; or
48 * choose mesh elements with the mouse in the 3D Viewer. It is possible to select a whole area with a mouse frame; or
49 * input the element IDs directly in **ID Elements** field. The selected elements will be highlighted in the viewer; or
50 * apply Filters. **Set Filter** button allows to apply a :ref:`filtering_elements` to the selection of elements.
52 * depending on the nature of the mirror object:
54 * if the mesh is mirrored through a point, specify the coordinates of the point, either directly or by picking a mesh node;
55 * if the mesh is mirrored through an axis:
57 * specify the coordinates of the start **Point** of the axis, either directly or by picking a mesh node;
58 * specify the components of axis **Vector**, either directly or by picking a mesh node, in which case **Vector** is defined as a shift between the **Point** and the node;
60 * if the mesh is mirrored through a plane:
62 * specify the cooordinates of the **Point** lying on the plane, either directly or by picking a mesh node;
63 * specify the components of plane **Normal**, either directly or by picking a mesh node, in which case **Normal** is defined as a shift between the **Point** and the node.
65 * specify the conditions of symmetry operation:
67 * activate **Move elements** radio button to change the location of the selected elements within the current mesh;
68 * activate **Copy elements** radio button to duplicate the selected elements at the new location within the current mesh;
69 * activate **Create as new mesh** radio button to create a new element in a new mesh; the new mesh appears in the Object Browser with the default name *MeshName_mirrored* (it is possible to change this name in the adjacent box);
70 * activate **Copy groups** check-box to put new mesh entities into new groups if source entities belong to some groups. New groups are named by pattern "<old group name>_mirrored".
72 * activate **Preview** check-box to show the result of transformation in the viewer;
73 * click **Apply** or **Apply and Close** button to confirm the operation.
76 **See Also** a sample TUI Script of a
77 :ref:`tui_symmetry` operation.