8

596 Chapter 12: Animation
to bring the yellow and red skeletons closer
together on a planted foot.
Note: Transitions involving planted feet often
result in one or both feet sliding when they
should stay planted. After setting up the
transition, you can correct this problem with
amixdown.See
Exporting Animation to the
Biped (page 2–601)
.
Adjusting Track Weight
Each track has one or more weight curves (page
3–1127)
that you can use to mix motion from
several tracks to varying degrees. The weight curve
determines how much a specific track contributes
to the motion within the trackgroup.
With weight curves, you can create several ful l
or partial transitions between all the tracks in
a trackgroup. Compare with transit ions on a
transition track (page 3–1121) ,whichcanonly
create a full transition between two clips.
Weig ht cu r ve s are u s e f u l for :
• Creating transitions between two tracks in a
trackgroup.
•Creatingrandommotion.
• Experimenting w ith transitions quickly and
easily.
Eachtrack’sweightcurveappearsasathinblack
line across the top of the track .
Tip: I f y ou can’t see the weight curve, click
Preferences to display the
Mixer Preferences dialog
(page 2–628)
. Tur n Weight Curves off and on and
watch the display to see the weight curve appear.
You access the weight curve by clicking the
Weight Mode button at the right end of the track.
Clicking Weight Mode on the Motion Mixer
toolbarenablesweightcurveeditingforalltracks.
When Weight mode is on, you can work only with
the weight curve, and not with clips.
You edit a weight curve using nodes (points) on
the c urve. Clips on layer t racks automatically have
a node at each end of each clip. A transition track
has no nodes by default.
Weight Cur ve Evaluation
By default, each t r ack’s weight curve is set to a
valueof1.0acrosstheentiretrack,whichuses
100% of the track’s motion in the mix. When
you change the cur ve to dip to a value below 1.0,
the motion on the track is mixed with the motion
on the track below it. For example, if you set the
weight curve for two tracks in a trackgroup to 0.5,
thetwoclipswillbemixedequally.
Several tracks can be stacked in a trackgroup with
varying weight curves on each one. For each frame
in the animation, the Motion Mixer evaluates the
curve on the topmost track. If its weight curve is
lessthan1.0atthatframe,theMixerevaluatesthe
next t rack down, and so forth. The Motion Mixer
adds up the weight curve values until the sum
reaches 1.0, a nd disregards tracks below t hat point.
For Transition tracks, one weight curve is used for
theentiretrack.OnLayertracks,weightcurves
are set individually for each clip.
Procedure
To adjust a weight curve:
1.
Open the Mixer, add a biped to the Mixer, and
create two tracks for a trackgroup. See
Filtering
Mixer Tracks (page 2–589)
.
2. Place different motion clips on the tracks.