8
1008 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 b oth) swing away
from their origin al vert ical alignme nt when the
biped is bent ov er.
See
Shifting the Biped’s Balance (p age 2–734)
.
Balance Track
Each biped added to the
Motion Mixer (page
2–581)
is automatically assigned a balance track.
You don’t place clips on this type of track as y ou
do with
transition tracks (page 3–1121)
and
layer
tracks (page 3–1055)
.The
weight curve (page
3–1127)
on the balance track is the only adjustable
parameter.
By default, the Motion Mixer compensates for
differences in upper and lower bo dy motion that
might cause the biped to go off balance over the
course of the animation. I t 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
2–599)
.
B allistic Gait
A "ballist ic 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 w hen the
biped lands or takes off from a jump or run step.
See
Adjusting Ver tical Motion (page 2–736)
.
B a r ycentr ic Coor dina tes
Given a triangle between points A, B, and C,
eachpointXonthesurfaceofthetrianglecanbe
represente d 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.
Thesenumbersarecalledthe
barycentric
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 barycentric 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 that 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.