2011

The basic operation of the Warp 2D tool involves drawing source and
destination shapes and linking pairs of these together. The correspondence
between points on the source and destination shapes defines constraints on
the transformation of the image.
Another type of shape constraint is a fence shape which functions like a pair
of source and destination shapes that are constrained to always be equal,
keeping a part of the image from moving from its source position. The resulting
transformation tries to make a deformation of 2D space that warps the image
to satisfy the specified shape positions, while automatically repositioning the
unconstrained parts of the image to make the overall warping as smooth as
possible.
The types of shapes supported include those in the Garbage Mask and Remove
Dust tool: Splines (open or closed), Rectangles, and Ellipses.
After drawing the shapes which define the transformation, you can set or
animate an interpolation parameter which controls the amount of warping.To
create a static warp of an image you will just set this to 1.Sometimes you may
want the image to smoothly change from its original shape to a warped shape
and will animate the interpolation parameter from 0 to 1.There is also a control
to use a per-shape interpolation amount to have various features deform at
different times.
Warping Workflow
The warping of a single image involves a multi-step process. You first work in
source space (by viewing the input image by pressing the 5 hotkey while
focused in the viewer) drawing several shapes which define the important
features that will be deformed and the fence shapes which will lock parts of
the image in place (like the dog's left eye down to its nose).
468 | Chapter 19 Warping