9

914 Glossary
the control vertices (CVs) of a B-spline affect only
their local region of the curve or surface. B-splines
alsocomputefasterthanBeziercurves.
Balance Factor
Balance Factor positions the biped’s weight
anywhere along a line that extends from the center
of mass to the biped’s head, affecting the degree
to which the hips or head (or both) sw ing away
from their original vertical alignment when the
biped is bent over.
See Shifting the Biped’s Balance (page 2–876).
Balance Track
EachbipedaddedtotheMotion Mixer (page
2–604) is automatically assigned a balance track.
You don’t place clips on this type of track as
you do with transition tracks (page 3–1027) and
layer tracks (page 3–961).Theweight curve (page
3–1033) on the ba lance track is the only adjustable
parameter.
By default, the Motion Mixer compensate s for
differences in upper and lower body motion that
might c ause the biped to go off ba lance over the
course of the animation. It accomplishes this by
changing the COM, pelvis and spine animation.
When the weight curve across the balance track is
set to 1.0 (the default), balance compensation is
enabled for the entire animation. You can adjust
nodes on the weight curve to disable balance
compensation over all or part of the animation.
See Adjusting Biped Balance in the Mixer (page
2–622).
B allistic Gait
A "ballistic gait" is defined as any footstep pattern
in which there are airborne periods (periods
w ith no feet on the ground) such as a jumping or
running pattern.
B allistic Tension
Cont rols the amount of spring or tension when the
biped lands or takes off from a jump or run step.
See Adjusting Vertical Motion (page 2–878).
B a r ycentr ic Coor dinates
Given a triangle b etween points A, B, and C,
eachpointXonthesurfaceofthetrianglecanbe
represented by a weighted sum of the corners:
X=a*A+b*B+c*C
where a, b, and c are numbers between 0 and 1 and
a+b+c = 1.
These numbers are called the barycentr ic
coordinates of the point X. There is one unique set
of barycentric coordinates for each point on the
triangle.
Examples
Thecenterofgravityofthetriangleisgivenbythe
barycentric coordinates (1/3, 1/3, 1/3): X = 1/3 A
+1/3B+1/3C=(A+B+C)/3.
If one of the barycen tric coordinates is zero, the
point X must lie on the opposite edge. For instance:
if a=0, X = b*B + c*C
where b+c=1
This means th at X is on the line segment BC.
If a=1, on the other hand, then b=c=0, and X must
be exactly the point A.