2009

It is best to use forward kinematics when you want the arms to swing, such
as when a biped is walking. In the case of a boxer, however, since the hand
should follow a directed path when punching, inverse kinematics should be
used.
To set the IK Blend value of a key:
1 Select a single arm or leg track by selecting one or more parts of a biped's
arm or leg.
The IK Blend spinner and the other controls in the IK area are enabled
only when a single arm or leg track is selected.
2 Set a key if one doesn't already exist.
3 Set the desired value of IK Blend.
Body and Object Options
By default, Biped calculates the kinematics solution using the coordinate
system of the biped figure's center-of-mass, or the Body coordinate system.
This means that the IK path of the hand (or foot) translates and rotates with
your character as it moves. For example, the boxer's hand trajectory always
moves relative to the weaving, bobbing, and turning of the boxer's body.
The Object option is used for animating dynamic links between the limbs and
other objects in the scene.
The IK Blend control activates when a biped arm or leg (hand and foot) key
is current.
■ 0 with Body turned on is
forward kinematics on page 7987, or normal biped
space.
■ 1 with Body turned on is
inverse kinematics on page 8016, creates more
straight-line motion between biped keys.
■ 1 with Object turned on, but no IK object specified, puts the limb fully
into world space. Use this to control foot sliding in a freeform animation.
■ 1 with Object turned on and an IK object specified puts the biped limb
into the coordinate space of the selected object; the biped limb follows
the specified object.
4262 | Chapter 17 character studio