Modeling and Animating Human Figures - Computer Animation: Algorithms and Techniques - page 300

(a) Start of stance (b) Midstance (c) End of stance

FIGURE 9.16
Position of pelvis during stance phase (sagittal plane). (a) Start of stance, (b) midstance, and (c) end of stance.
Box indicates supporting contact with floor.

2

4

1 3

5

FIGURE 9.17
Transport of pelvis by intersecting circular arcs (sagittal plane).

Start of stance Midstance End of stance

FIGURE 9.18
Pelvic orientation during stance phase (transverse plane).

lengthen the stride as the swing leg stretches out for its new foot placement. This rotation of the pelvis
above the stance leg means that the center of the pelvis follows a circular arc relative to the top of that
leg. The top of the stance leg is rotating above the point of contact with the floor ( Figure 9.18 ), so the
path of the center of the pelvis resembles a sinusoidal curve ( Figure 9.19 ) .

Pelvic list
The transport of the pelvis requires the legs to lift the weight of the body as the pelvis rotates above the
point of contact with the floor ( Figure 9.20 ) . To reduce the amount of lift, the pelvis lists by rotating in
the coronal plane.