When you use footsteps
to animate the legs and feet, animating the spine, neck, head, arms,
and other upper body parts is accomplished in the same way as for
freeform animation. Simply turn on Auto Key and start moving and
rotating body parts. See
Animating by Moving Links and
Animating by Rotating Links.
can also click the Set Key button on the
Info rollout to set keys for selected
body parts at the current frame. This option allows you to move
body parts as you like, setting keys only when you have decided
to do so.
use the 3ds Max Set Key button to set keys for the biped.
Animation on the center
of mass (COM) works differently, depending on whether the biped
is in a footstep at that particular frame.
- If at least one foot is in a footstep,
moving or rotating the COM will animate the entire body along with
the COM, except a foot that is in a footstep. A foot in a footstep
will stay planted in the footstep and the leg will bend or straighten
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. This is because character
studio automatically calculates how high the biped can
go based on the biped's height and the current gravity setting.
To make the biped jump higher or lower during airborne periods,
Animation Between Footsteps.
Working with Existing Keys
Because keys are created
for the spine, arms, and tail when footsteps are activated, you
will want to take care when creating new keyframes. As with 3ds Max animation,
placing keyframes one or two frames apart creates jerking or popping
To avoid placing keyframes
on upper body parts 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
- Delete all the body part keys except
the key at frame 0, and create entirely new keys throughout the
WarningIf 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.
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 of the body's center
of mass, leg positions are automatically updated to ensure the feet
still move from footstep to footstep.
the upper body and legs are updated after a key has been 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 automatically
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 relationships allows you easily to experiment and
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, and pelvis cause the legs to adjust.
Changes to the legs do not affect the center of mass's vertical position.