Rest
Angle Editing
A kinematic
solution's rest angles are used by the solver to define the way
in which the chain reacts as the goal is moved. The rest angle for
each bone is set to 0, 0, 0 when a bone is first drawn although
the actual angles are defined in the bone's pre-transform values.
You can middle mouse button on a bone in the network view to find
out what these values are. Using the kinematic override method,
you can adjust the rest angles after the bones have been drawn to
change how the chain is solved.
1.
Setting up a sample bone chain
Select tab
> Character > Bones and set Kinematics
to Inverse Kinematics.
Click to place a root and two bones to form a simple arm with the
elbow set a little to the left. With the Pose
tool, edit the end effector to show that the elbow is bending in
the chosen direction.

2.
Edit the Rest Pose
Select Settings
> Objects > Kinematic Override: Rest.
This turns off the IK goal's control on the chain and the bone rotations
pop back to their default rest angles. With the Transform
tool, select the forearm bone and rotate it until it is bent in
the opposite direction from the original setup. Select Settings
> Objects > Kinematic Override: None and
with the Pose
tool, edit the end effector to show that the elbow is bending in
the opposite direction.

Tip:
The new rest angle adjustement is set as a bone parameter.
To find these values, select the bone and click on the Bone tab
in the Parameter pane. The Rest Angles parameter will show the angular
offset from the original 0, 0, 0 settings.
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