You can use the HumanIK roll bone system to add a maximum of five roll bones per limb, giving you greater control over the rotation of your character's upper arms, lower arms, upper legs, and lower legs.
Roll bone controls in the Attribute Editor let you define how you want a character's roll bones to behave as you rotate the character limbs. See also Roll nodes.
To define roll bone behavior
- Do one of the following:
- Create a new default skeleton with up to five roll bones per limb. See Create and define a HumanIK skeleton and Skeleton setup area.
- Define an existing skeleton with roll bones. See Define an existing skeleton for HumanIK.
- In the HumanIK window, ensure the character you want to work with is selected as the current Character.
- Select
>
Edit Character Definition > Edit HIK Properties.
- In the HIKProperties tab in the Attribute Editor, expand the Roll & Pitch heading.
- For each roll bone defined for your character, use the
Roll sliders to define the degree to which each target roll bone is influenced when you rotate the associated character limb.
You can map a maximum of five roll bones per limb. All roll bones are parented to the same limb bone, and the placement of roll bones along the bone and the percentage of rotation per roll bone is determined by the number of roll bones per limb. By default, values are assigned to each roll bone in the Left Leg, Right Leg, Left Arm, and Right Arm sections in the HIKProperties tab. Adjust these values to change the percentage of rotation per roll bone.
For example, if there is a Left Fore Arm Roll 1 bone defined, the Left Elbow Roll property controls the distribution between the left forearm roll and the elbow. Setting the Left Elbow Roll slider to 0.500 means that 50% of the left elbow roll will be distributed between the left forearm and the left elbow roll as you rotate the left arm.
(If there is no Left Forearm Roll 1 bone, then Left Elbow Roll controls the distribution between the left hand and the elbow.)
Note: If a roll bone is not defined for the current character, the associated Roll slider is set to a default value of 0.