Apple Shake 4 - Manual (Page 829)

Chapter 27 Warping and Morphing Images 829
For example, if you want to isolate a warping operation to a particular region, you can
create a closed boundary shape to lock off just that area. Sometimes, you may have to
use several concentric rings of boundary shapes to completely lock down an area of
the image. You can also use open boundary shapes to “pin down” specific areas of an
image that you don’t want to be affected by a warping effect. For example, if you were
creating a warp effect to manipulate an animal’s face, you could use a combination of
open and closed shapes and single-point shapes to prevent the eyes and nose from
being affected by the warp you’re applying to the eyebrow area.
Note: By default, the outer edge of the frame is also used as a boundary shape, by
default. This behavior can be disabled by turning off the addBorderShape parameter in
the Parameters tab for the Warper or Morpher node you’re adjusting, but this may
produce unexpected results.
Isolating the Subject of Deformation Prior to Warping or Morphing
Even when you use one or more boundary shapes to pin down areas surrounding a
warp effect, you may find that some of the surrounding image is still affected, however
slightly. For this reason, it may be useful to isolate the subject of the image prior to
using either the Warper or Morpher node. Ideally, the subject of the warp effect was
shot against bluescreen or greenscreen, and can be keyed. If not, you can always
rotoscope the image using a RotoShape node.
In either case, the Warper and Morpher nodes affect the alpha channel of the image
along with the RGB portion, so you can always add either node to the tree after you’ve
isolated your subject by keying or rotoscoping. This way, you can add a clean
background no matter how extreme the warping effect is.
Closed
boundary
shape
Open
boundary
shapes