Character Animation: The Fun Part - Blender Foundations: The Essential Guide to Learning Blender 2.6 - page 314

time. For example, when adding overlap to the motion of the head, neck, and spine, where does the force
or motion begin? If your character gets kicked in the chest, throwing him or her backward, the spine will
move first, followed by the head, then the neck. However, if your character is turning his or her head to
look at something, the head will move, followed closely by the neck, then the rest of the spine. The two
situations show different motive forces, and will look very different depending on how you build the
overlap.
The Web Bucket video holds_plus_overlap.mpeg shows the same section as the previous video, but includes
overlap. The difference is subtle but noticeable. I've compiled both videos into a side-by-side demonstra-
tion for direct comparison, called effect_of_overlap.mpeg .
Let's recap before tackling the walking animation. To create character animation, we begin by creating a
series of poses in constant interpolation mode, with attention being paid to such things as balance, weight,
and symmetry. Keys are inserted for all bones in the armature on each of these keys. Basic timing is esti-
mated. If the character will be walking, the legs and feet are temporarily ignored. After the initial posing
is complete, the animation is released to Bezier interpolation. Then, moving holds are added to correct
the velocity of the pose transitions. Motions are also adjusted so that different parts of the body act together,
but not perfectly in sync. Finally, overlap is added to hint at the origins of force.
Walking
It's interesting that such a mechanical process as the one we've just worked through can lead to things
that appear to be alive, if we're doing our job. That notion goes double for walking. As we discussed
before, walking is the process of making your feet land underneath you in such a way that you maintain
your balance as you hurl your body through space. It's probably one of the most mechanical things that
people do. So too is the process of animating it. This isn't to say that you can't add character to a walk.
You certainly can. But the actual motions of the feet—the way they contact the ground and position
themselves—is pretty much dictated by physics.
To get started, find the lower body mesh and re-enable it for the layer with the rest of our animation
objects. If you want some amusement, press Alt-A and watch the legs stre-e-e-e-tch as the character's
upper body moves. In accordance with our theory about walking, we're going to find the first frame on
which the body begins to move, then step to the end frame by frame, keying the feet in order to keep
everything in balance.
You're going to need a large 3D workspace and a timeline view for this, and not much else. I created a
special screen for working on a walk that contains only those two types, shown in Figure 11.25 . LMB
drag in the timeline to scrub the animation back and forth until you find where the body begins to move.
This is your starting point.
By scrubbing in the timeline back and forth over the point where the body begins to move, it's pretty
obvious that the right foot needs to go first. Here's the procedure for walking:
1. Determine the frame on which the back foot needs to leave the ground. In the case of the example
file, this is frame 50. How do you tell? Usually, it's when the leg can no longer withstand the motion