Warp > Stretch Operation > About Stretch, Bend, and Twist Operations
  
About Stretch, Bend, and Twist Operations
To adjust the region of deformation, drag the top, bottom, left, right, back, or front face of the marquee. For example, if the stretch axis is in the direction of the x-axis, drag the right and the left faces of the marquee to adjust the region for stretching. If the stretch axis is in the direction of the y-axis, drag the top and the bottom faces of the marquee to adjust the region for stretching. Alternatively, click the Marquee tab and set one or more of the marquee options.
 
* Preselection highlighting is available in Warp. When the pointer is over the face of a marquee, the face gets highlighted if it can be used to limit the region of deformation
Bend
The damping function gradually reduces the bend angle from one side of the marquee to the other.
Pivot is the point on the bend axis about which the geometry bends. You can move the pivot between the start and the end of the bend axis. At the ends, the pivot value is 0 and 1. The pivot is exactly midway between the two endpoints when the pivot value is 0.5.