9

1006 Chapter 14: character studio
Because pivots are located in all extremes of the
hands and feet, t heir trajectories discontinuous
when both FK and IK periods are employed.
The following figure shows a simple example of
this. During the planted IK periods, the pivot
trajectories show just the keys on the heel and toe
(because the keys are planted, each pivot stays in
place), and during the FK periods the trajectories
arederivedfromthefoot’snodepivotlocation.
This gives you more-detailed information about
the animation that is driving the foot.
Footstep trajectory
In following illustration, while the biped walks,
the right hand reaches up to touch something
in IK, as shown by the yellow trajectory, made
by two sliding IK keys. Later, the biped touches
its own face, using b ody space IK, as shown by
thebrightbluekeys.Thecolortransitioninthe
trajectory from purple to blue indicates a changing
blend from FK to body-space IK, showing the
interpolated value of the IK Blend parameter.
Hand trajectory
Followingisachartshowingtheresultofgoing
from one key type to another. the last three rows
of the chart show t ransitions between object and
body space that produce pure FK. In the past, it
was hard to know what type of trajectory these
combinations produced. The new trajectory colors
clarify the result.
In t he chart, the letters have the following
meanings:
•O:objectspace
•B:bodyspace
•IK:akeywhereIKBlend>0.Itisalways
accompaniedbythespace:OorB.
• FK: a key where IK Blend = 0, no matter what
space it’s in
Fr om -> To
Result
Tra je ctory
Drawn
Tra je ctory
Color
OIK -> OIK OIK Pivot
Yellow
BIK -> BIK BIK
Node Blue
FK -> FK FK
Node Purple
BIK -> BFK BIK/BFK
blend
Node Blue ->
Purple
OIK -> OFK OIK/OFK
blend
Node Yellow ->
Purple
OIK -> BIK FK
Node Purple
OIK -> BFK FK
Node Purple
BIK -> OFK FK
Node Purple
Note: When separate tracks exist for either a limb
or its digits, the FK trajectory of the bone base is
always drawn, regardless of whether the trajectory
display is set to Bone Base or Bone Tip on the
Display Preferences dialog (page 2–944).
Biped Shortcuts
The table in this topic shows the default keyboard
shortcuts for character st udio. To customize your
shortcuts, use the path specified above.