Symmetric Modeling with Move Tool Reflection Mode
Maya 2012 Tutorial
How to Create a Symmetric Object Using Move Tool in Reflection Mode in Maya
The Move tool (w key) Reflection option allows you to quickly create symmetric models. Once the Reflection axis is set, each of the non-seam points on the object has a mirrored twin. Reflection works with vertices, edges and faces.
Add a polygon plane to the workspace by choosing Create > Polygon Primitives > Plane (include options).
In the options, set the Width, Height and Divisions to 10. Click Create to add your plane.
Double-click the Move tool (w key) to open the Move tool options.
Open the Reflection Settings section and click the Reflection checkbox. Set the Reflection Axis to x.
Right-click the plane and choose Vertex from the menu.
Select one or multiple points and drag them with the Move tool (w key). Notice that whenever a point is moved, it's mirrored twin also moves to maintain the symmetric shape.