9
Animating Pivots 905
Wa rning: Do not use the large Set Key button, found
below the viewports, when animating a biped. Doing so
will cause unpredictable results. Instead, always use the
Set Key buttons found on the Key Info rollout.
If you are animating a walk cycle or
an intricate hand animation, then you should make
use of the three different types of set key buttons
in the Key Info rollout. E ach set key button applies
different IK constraints, depending on whether a
foot or finger is in a planted state, a move state, or
a sliding state. For more information on the three
set key buttons, see Key Info Rollout (page 2–954).
You can als o set keys to make hands and feet follow
astationaryoranimatedobject.SeeAnimating IK
Attachments (page 2–908).
If a Bones system using the IK controller or a
part icle emitter is linked to the biped, the Auto Key
button must be on in order to position the biped’s
limbs. This is also true for biped objec ts if you turn
on 3ds Max Trajectories at the top of the Motion
panel, or if you choose Views > Show Ghosting.
TheSetKeyoptionsontheKeyInforollout
have the advantage that you can easi ly experiment
with different poses for your character without
unintentionally setting keys as a side-effec t. Use
the Set Key buttons to commit the changes you
make to the pose. The Auto Key mode approach
is especially useful when you make adjustments
to keyframes that have already been set, or if you
are used to working with Auto Key in3ds Max and
tend to forget to click the Set Key buttons.
Tip: UseSetKeytoinsertakeyonaframewhere
a key doesn’t exist. You’ll often want to refine the
motion using controls in the Key Info rollout,
w ithout selecting and moving an object in the
viewport.
K eyboard shortcut: Pressing 0 (zero) is equivalent
to clicking Set Key on the Key Info rollout.
To u s e character studio-specific shortcuts,
make sure that the Keyboard Shor tcut Override
Toggle (page 3–872) is active.
Gr ound Pl ane Coll ision Detection for the
Pelv i s a nd Feet
When one or two feet are planted, and the pelvis
or a planted foot is rotated, character studio
detects collisions of the foot and its to es with the
ground plane defined by the planted foot’s footstep
or pivot point. As the pelvis or foot is rotated,
character studio uses inverse kinematics to alter
the rotations of the l eg joints so that the foot and
itstoesdonotgobelowtheplanedefinedbythe
footstep or pivot point.
Note: A biped foot on a sliding footstep is a special
case.Thebipedfootcanbemovedtoanyposition
and orientation for the duration of the footstep.
Note: Changing rotation values for the legs and toes
also maintains collision detection, but the position
adjustment is not made until you set a key.
Animating Pivots
In both freeform and footstep animation, pivots
allow you to rotate the biped’s hands and feet
around various points. For example, by activating
a pivot on the ball of a foot, you can rotate the foot
around the ball of the foot. The biped’s hands and
feet have the same number of pivots, and pivot
location is similar. Pivots are active only if the
biped hand or foot is in world or object coordinate
space. In a walking motion, you can pivot on the
heel first, then on the ball of t he foot, and finally