Walks are very complex. Not only do the feet have to move across
the ground, but the hips, spine, arms, shoulders and head all move
in sync to maintain balance in the system. Though complex, if you
break down each of these movements joint by joint, the mechanics
of walking become clear.
Letís break down a basic walk, step by step. For clarity, Iíve animated
a simple skeleton so you can see exactly how each joint moves.
THE FEET AND LEGS
The feet and legs propel the body forward. To keep your character
looking natural, you should always keep the joints bent slightly,
even at full leg extension.
walk usually starts with the feet at the extended position
Ė where the feet are furthest apart. This is the point where
the characterís weight shifts to the forward foot.
the weight of the body is transferred to the forward foot,
the knee bends to absorb the shock. This is called the recoil
position, and is the lowest point in the walk.
is halfway through the first step. As the character moves
forward, the knee straightens out and lifts the body itís
highest point. This is called the passing position because
this is where the free foot passes the supporting leg.
As the character
moves forward, the weight-bearing foot lifts off the ground
at the heel, transmitting the force at the ball of the foot.
This is where the body starts to fall forward. The free
foot swings forward like a pendulum to catch the ground.
free leg makes contact. This is exactly half the cycle.
The second half is an exact mirror of the first. If it differs,
the character may appear to limp.
HIPS, SPINE & SHOULDERS
The bodyís center of gravity is at the hips -- all balance starts
there, as does the rest of the bodyís motion. During a walk, itís
best to think of the hipsí motion as two separate, overlapping rotations.
First, the hips rotate along the axis of the spine, forward and
back with the legs. If the right leg is forward, the right hip is
rotated forward as well. Second, at the passing position, the free
leg pulls the hip out of center, forcing the hips to rock from side
to side. These two motions are then transmitted through the spine to the shoulders, which mirror the
hips to maintain balance.
the feet are fully extended, the hips must rotate along the axis
of the spine. To keep balance, the shoulders swing in the opposite
direction. From the front, the spine is relatively straight, but
from the top, you can see how the hips and shoulders twist in opposite
directions to maintain balance.
the passing position, the front view shows the hip being pulled
out of center by the weight of the free leg. This causes a counter-rotation
in the shoulders. From the top, however, the hips and shoulders
are nearly equal angles.
the extension of the second leg, the hips and shoulders again are
flat when viewed from the front. From the top, however, you can
see the rotation of the hips and shoulders has completed.
Unless the character is using itís arms, theyíll generally hang
loose at the sides. In this case, they generally act like pendulums,
dragging a few frames behind the hips and shoulders.
Even at full extension, try keeping the arms slightly bent at the
elbows. This will keep them looking natural.
In a standard walk, the head generally tries to stay level, with
the eyes focused on where the character is going. It will then bob
around slightly to stay balanced. If a character is excited, this
bobbing will be more pronounced. The head may also hang low for
a sad character, or may look around if the scene requires it.