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Adjusting Body Keys in Track View 875
the footstep and the leg will bend or str ai ghten
as the COM is moved up or down.
• If the biped is airborne (no footsteps at that
frame), the COM can be moved horizontally
and can be rotated, but cannot be moved
vertically.Thisisbecausecharacter studio
automatically calculates how hig h the biped can
go based on the biped’s height and the current
gravity s etting. To make the biped jump hig her
or lower during airborne periods, see Freeform
Animation B etween Footsteps (page 2–883).
Working with Ex isting K eys
Because keys are created for the spine, ar ms, and
tail when footsteps are act ivated, you will want to
take care w hen creating new keyf r ames. As with
3ds Max animation, placing keyf rames one or two
frames apar t creates jerking or popping motions.
To avo i d p l a c i n g key f r a m e s o n u ppe r b o d y p ar t s
too close together, you can do one of the following:
•
Turn on the 3ds Max Key Mode toggle,
select the body part, and use Next Key and
Previous Key to move in time from one
keyframe to another. Animate only on existing
keyframes.
• Deleteallthebodypartkeysexceptthekey
at frame 0, and create entirely new keys
throughout the a nimation.
Wa rning: If you delete all keys, including the key
at frame 0, be sure to set a key at frame 0 before
animating on other frames. character studio does
not automatically place a key at frame 0 when you
animate on frames other than 0, as 3ds Max does.
Inter dependencies Bet ween Legs and
Upper Body
When footstep animation is used, animation of
the upper body and animation of the legs are
interdependent. Any time you change the position
ofthebody’scenterofmass,legpositionsare
automatically updated to ensure the feet still move
from footstep to footstep.
Interdependencies between the upper body
and legs are updated after a key has b een set,
sometimes causing the appearance of a pop in the
leg position. However, in playing the animation
you will find the motion to be smooth.
When you set a leg key while the foot is on the
ground, the location of the foot is automa tically
recalculated based on the natural roll of the foot
from its point of initial contact with the ground.
The pivot points are based on collisions between
the footstep plane, the two corners of the heel, and
the bones that connect the toes’ links.
This ability to preserve interdependent
relationshipsallowsyoueasilytoexperimentand
improvise with motion, since you are assured
that edits to one body part will not corrupt the
integrity of other parts.
In general, changes to the center of mass, spine,
andpelviscausethelegstoadjust. Changesto
thelegsdonotaffectthecenterofmass’svertical
position.
Adjusting B ody K eys in Track V iew
When you activate footsteps, keys are created
forbipedbodyparts.Afteractivatingfootsteps,
you c an also create keys by turning on Auto Key
and animating body p arts. All these keys can be
viewed in Track View – Dope Sheet mode.
In general, editing biped body keys in Track View
isthesameaseditingkeysofanysortin3dsMax,
with a few restrictions.
Before reading this section, please read
Understanding Footstep and Body Keys (page
2–867) for terms and definitions used in this
section.