Facial Motion and Controls - Animating with Blender: How to Create Short Animations from Start to Finish - page 183

alignment that might look good in the orthogonal view of the 3D window could look cross-eyed or
cock-eyed from a perspective render.
● Apply any transformations to the eye objects with Ctrl-A .
● Create a new bone called something like “sight_target” in the character's control armature midway
between the eyes and standing about a foot away from the character's face in the scale of your model.
● Using the snap tools ( Shift-S in the 3D view), create a new bone that begins at the center of an eye and
ends at the base of the “sight_target” bone. Call it “sight_line_R” (or “_L”).
● In Edit mode on the armature, make the “sight_line” and “sight_target” bones children of the main head
bone so that they move with the rest of the head.
● In Pose mode, add an IK constraint to this “sight_line” bone, setting “sight_target” as its target. Make sure
to set the IK chain length to 1 or moving the eye controller will cause your entire character rig to go crazy.
At this point, moving the “sight_target” bone in pose mode should have the two “sight_line” bones (one for
each eye) follow it.
● Return the “sight_target” to its rest position ( Alt-G , Alt-R ).

● Right mouse button select an eye, then Shift right mouse button select the corresponding “sight_line” bone.
● Press Ctrl-P to create a parent/child relationship and choose Bone from the menu that pops up. This
ties the eyeball as a whole object directly to that bone. Repeat the procedure for the other eye or as
many times as your character has eyes.
● Moving the “sight_target” will now move the eyes.

When animating with this system, it is easy to control the character's gaze. Under normal circumstances, the
sight target will move with the head, causing the eyes to move along with it. Moving the target closer to the
face makes the character go cross-eyed, while moving it away makes the character appear to gaze into the
distance. It is also simple to use a CopyLocation constraint on the sight target to fi x the character's focus to a
specifi c object or location.

Flattened, Squashed or Otherwise Nonspherical Eyes

Many more stylized or cartoonish char-
acters will require eyes that, due to the
design of the character, cannot be spheri-
cal. Figure 10.40 shows a fi sh character
with eyes that are obviously nonspherical.
In this example, there is no way to rotate
the eye around the X-axis without having
it protrude horribly from the character.
The challenge is to create an object for
the eye that can somehow rotate within
an ellipsoid eye socket.

Unfortunately, there is no such object.
You can fake it, though, with the steps

Figure 10.40 Note the vertically stretched eyes