Manipulating Components Symmetrically
Symmetrical manipulation lets you manipulate points and other components and maintain the symmetry of an object. Any manipulation performed on components on one side are mirrored to the corresponding components on the other side. Components that lie directly on the plane of symmetry are “locked down”; they can be translated or moved only along the plane of symmetry itself.
There are two basic ways of manipulating symmetrically:
• In “live” mode, Softimage finds the symmetric components onthefly. This requires that the object’s current shape is symmetric.
• With a symmetry map, there is a permanent correspondence between symmetric points. This means that corresponding components can still be moved automatically even if the object is no longer symmetrical, for example, if an envelope, a twist, or any other deformer has been applied.

Symmetry mode does not work with hair. 
Activating Symmetrical Manipulation
To toggle symmetry mode on or off, click Sym on the Transform panel.
• If there is a symmetry map on the object, it will be used.
• If there is no symmetry map, the settings in your Symmetry preferences are used instead. You can rightclick on Sym to quickly choose a plane of symmetry or choose Symmetry Properties to set more options. See Symmetry Preferences [Preference Reference].
Component manipulation in Sym mode works with the following tools:
• Scale tool on points, edges, and polygons (X key)
• Rotate tool on points, edges, and polygons (C key)
• Translate tool on points, edges, and polygons (V key)
• Tweak Component tool on points, edges, and polygons (M key)
• Tweak User Normals tool
• Move Point tool
• View Plane Pivot Transform tool on points, edges, and polygons
• Paint Push and other brushbased tools
• Nudging
A symmetry map establishes the correspondence between points on either side of the plane of symmetry.
To apply a symmetry map
1. Select a geometric object.
2. Choose Get > Property > Symmetry Map from any toolbar. A property editor opens.
3. On the Symmetry Map Generator property page, set the Symmetry Plane to the desired value: YZ (X = 0), XZ (Y = 0), or XY (Z = 0). The symmetry map uses the object’s local center and the chosen plane to establish a correspondence between points.

Symmetry maps are not updated after topological operations. If you make any modifications that create or remove components on the object, you should delete and reapply the symmetry map. 
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