8

Work ing with Freeform Animation 745
Deleting and inserting keys or changing IK space
or IK blending alters footstep d uration.
Incasesinvolvingeditsthatalterthelengthof
ballistic inter va ls (when a biped is airborne),
the s oftware ensures that there is a vertical key
occurri ng at the lift-off and touchdown frames.
This calculates the correct ballistic motion, so
vertical keys are automatically inserted if not
present.
There are three types of IK keys you can create:
planted , sliding and free keys.
• Planted keys have an IK Blend of 1. They are
joined to the Previous IK Key and are in Object
space, rather than B ody space. Planted keys
lockthefootorhandtotheground,ortoany
object.
• Slid in g keys have moving IK constraints.
Sliding footsteps are created if there is a
moved
IK constraint occurring in the footstep interval.
In a footstep animation this means that the foot
can be placed anywhere, even though there is
a footstep icon. Footstep icons can be thought
of as gizmos rather than the absolute location
of a fo ot. Sliding keys have an IK blend of 1,
and are in object space, but are not joined to the
previous IK key.
• Free ke y s have an IK blend of 0, and are in body
space. They are not joined to the previous IK
key. Free keys have no IK constraint.
IK constraints are implemented with a pivot-based
system. This allows you to pivot a hand or foot
around a selected pivot. For example, in a walking
motion you can select a pivot on the heel of a foot
and rotate the fo ot around it,. You can then shift
the pivot to the ball of the foot.
Pr ocedur es
To crea te a pu r el y f r eef or m an im a ti on :
1.
Create a biped.
2. Movethetimeslidertoanygivenframethendo
one of the following:
•
Turn on Auto K ey, then move or
rotate any biped component. This sets a key
for that component.
•
Pose any part of the biped, then in the
Key Info rollout, click Set Key .
•
Pose the hands and feet and then in the
Key Info rollout click Set Planted Key . This
will create keys that cause the hands or feet
to stick in space.
For more information on setting k eys, see
Setting Keys for Feet and Hands (page
2–762)
.
Note: character studio doesn’t behave the
same as 3ds Max when creating keys. It doesn’t
automatically create keys at frame 0 when you
create your first set of keys at a later frame. For
this reason, it’s often useful to select all the
parts of the biped at f rame 0, then click Set Key
to creating holding keys for all.
To create a f reef rom ani mati on f r om a footstep
animation:
1.
Selectthebipedwhosefootstepanimationyou
want to convert to freeform.
2. On the Motion panel Biped rollout, click
Convert.
A C onvert To Freefor m dialog is displayed.
Click OK.
Don’tturnonGenerateAKeyframePerFrame
unless you have a good reason to do so. Having
a keyframe on ever y frame makes animation
editing much more complex. Use this only
if you are losing motion quality through a
conversion process.