IK Setup
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Similar to retargeting, IK setup can be found by selecting a bone on the character or scene tree. Then, in the Inspector tab, click the “IK Setup” button.
Similar to retargeting, IK setup automatically best-guesses each relevant limb bone to match the IK slot. This can be changed by clicking on the target icon slot, which will open a dropdown of all the bones to choose from. Pick the bone that is used as the end effector bone.
Press “Create” to create the relevant IK type, then “Save”. To quit IK setup mode, press “Cancel”.
There are 2 IK Types for Feet IK
Normal IK (three bone chain, also the default type for Hand IK) and Reverse Foot (four bone chain).
A typical Normal IK setup for the left leg is as follows: Left Thigh, Left Knee, Left Foot (end effector). The Reverse Foot setup would be as follows: Left Thigh, Left Knee, Left Foot, Left Toe (end effector).
IK controls are represented as a white torus ring handle. Left click on the IK handles to adjust settings and test the animation on the impacted bones. Right click to force IK to stick to its position irrespective of the root node. (IK pinning = ON)
FK/IK Blend: The amount to blend the underlying character mesh between FK vs IK. If value is 1, the character mesh will follow the IK chain. If value is 0, the character mesh will follow the FK chain.
Pole Angle: Angles in degrees representing the direction that the middle joint in the IK chain should point to. E.g. the rotation of knee
For a cleaner look, the FK bones will be hidden when the value or IK blend is at 1 and vice versa.
The Reverse Foot IK consists of all settings from Normal IK, with one additional Foot Rotation property.
Foot Rotation. Defines how much the foot rotates along the IK handle in the X (forward), Y (twist) and Z (bank) angles. Hold Shift + Drag on the rotation gizmo to trigger foot rotation.
The Foot Rotation property offers more control over how the foot rolls, twists or moves forward relative to the IK handle. In this example, the Foot Rotation X is set at 40 degrees, indicating a forward angle. This creates a “tip-toe” effect without needing to adjust the rotation of the actual IK handle.
For best results, Reverse Foot requires the IK handle to be placed parallel to the ground (XZ axis, Y value = 0) during setup. This can be adjusted by clicking on the Reverse Foot handle and then clicking the “Adjust Foot” sub-tab in IK mode.
When “Adjust Foot” is in effect, moving the IK handle will not animate the IK bone chain. Instead, this mode is used to adjust the position and rotation of the IK handle with respect to the foot (or toe) node.
GOOD The position and rotation fit the foot to ground placement, and the size is appropriate (defined by the 4 adjustable pivots: front, back, left, right).
NOT GOOD Both the position and rotation are not well placed relative to the foot.
Once you are satisfied with the overall IK setup, press “Apply”. This will redirect you back to Animation mode, with the new IK handles created for the character in the scene.
