Problem

You cannot add full body IK effectors to a character that is already animated with traditional FK, IK, or motion capture data. You can only create FBIK effectors for characters with no previous animation.

Solution

1. Duplicate your character’s skeleton without the keys.
2. Create the full body IK effectors for the duplicate skeleton.

   See Prepare your character for full body IK, FBIK joint labelling and naming conventions, and Create the full body IK system for your character.

3. Turn on the display of the FBIK FK skeleton.

   Select Skeleton > Full Body IK > Show FBIK FK Skeleton.

4. Alternatively, set up the original skeleton as an HIK character and retarget the animation to another HIK character.

   See Retargeting workflow.

Problem

Characterization may fail and an error may occur when your character’s HipsTranslation joint is not properly positioned in the scene view or in your character’s joint hierarchy.

Solution

• Place the HipsTranslation joint above the Hips joint in your character’s joint hierarchy
• In the scene view, move the HipsTranslation joint to the same Translate X, Y, and Z coordinates as the Hips joint.

Problem

Creating FBIK effectors for a character that has a HipsTranslation joint may corrupt the character’s skinning if your character’s HipsTranslation joint is not properly positioned in the scene view or in your character’s joint hierarchy.

Solution

• Place the HipsTranslation joint above the Hips joint in your character’s joint hierarchy.
• In the scene view, move the HipsTranslation joint to the same Translate X, Y, and Z coordinates as the Hips joint.

Problem

Your pinned FBIK effectors translate and rotate during playback. This is because pinning only affects your FBIK effectors during interaction—not during playback.

Solution

To constrain a FBIK effector in rotation or translation during playback, set an IK key on the FBIK effector. The IK key will anchor your effector and prevent it from being transformed by movements in other parts of the body.

Problem

If you constrain your FBIK effectors to other objects (for example, control objects), your character’s FBIK IK animation (input skeleton) will not follow its FBIK effectors. This is because during playback, FBIK is only activated for effectors whose Reach values are set to 1.0 (pure IK), and constraining your effectors causes your Reach values to become values other than 1.0.

Solution

Set the constrained FBIK effectors’ Reach values to 1.0 (pure IK).

Problem

Some of your character’s joints or segments of geometry appear out-of-scale with their parent joints or other geometry. This can occur if you have the Segment Scale Compensate attribute for a joint turned on. When Segment Scale Compensate is on, scaling parent joints also scales lower joints in the chain, a process that conflicts with the FBIK solver.

Solution

The Segment Scale Compensate attribute is automatically turned off when you load an FBIK rig. If you experience out-of-scale geometry or joints, make sure that you have Segment Scale Compensate turned off.

See Segment Scale Compensate for more information on this attribute.