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Character Setup

Pose and animate your character with full body IK

Full body IK uses multiple levels of hierarchy. These levels of hierarchy are used to group your characters, effectors, joints, and even animation keys according to the anatomical structures of your character’s body. When posing your characters with FBIK, you will have to work with your character’s FBIK effectors and skeletons. When animating your characters with FBIK, you will have to work with your character’s body parts and character sets.

When you add full body IK to your character, the following levels of hierarchy are created:

• A FK skeleton and a set of FBIK effectors are created for your character, and your character’s original skeleton becomes its input skeleton. See FBIK skeletons and effectors.
• Each of your character’s FBIK effectors and FK joints are made members of a body part. See Body Parts.
• A top-level character set is created for your character and a series of subcharacter sets are created for each of your character’s body parts; all to house your character’s animation keys. See Character and subcharacter sets.

FBIK skeletons and effectors

When you add full body IK to your character, a FK skeleton and a set of FBIK effectors are created, and your character’s original skeleton becomes its input skeleton. For FBIK to work, the hikSolver requires both the input and FK skeletons.

In the scene view, the input skeleton appears brown and the FK skeleton appears dark blue. To make the FK skeleton visible in the scene view, select Skeleton > Full Body IK > Show FBIK FK Skeleton or Hide FBIK FK Skeleton.

During interaction, the hikSolver synchronizes your FK skeleton and the input skeleton driven by the FBIK effectors. Also, advanced FBIK attributes like Pull and Stiffness are not taken into account during interaction. See hikHandle in the Character Setup guide.

During playback, your FK and input skeletons contribute to the resulting FBIK animation, but they are no longer synchronized.

Input skeleton

When posing with FBIK, you can transform the joints of your character’s input skeleton to create joint-level poses. This is similar to posing with regular FK in Maya. See Posing skeletons in the Character Setup guide.

When animating with FBIK, you can key the joints of the your character’s input skeleton and their FBIK effectors to create FK animation. Any keys you set on the input skeleton are not actually placed there, but are instead placed on the FK skeleton.

When playing back your FBIK animation, the input skeleton shows the resulting FBIK animation in the scene view, similar to the blend skeleton when blending IK/FK animation. See IK/FK blending in the Character Setup guide.

The input skeleton is also used to bind your character’s skin.

FK skeleton

When posing with FBIK, you do not transform the joints in the FK skeleton, but instead you manipulate the joints in the input skeleton to create FK-type poses.

When animating with FBIK, you do not key the joints of your FK skeleton, but instead you key the joints of your input skeleton and their FBIK effectors to create FK animation. However, the keys that you set on the input skeleton are placed on the FK skeleton.

When playing back your FBIK animation, your can show the FK skeleton to view the differences between your character’s input and FK skeleton’s poses.

FBIK effectors

When posing with FBIK, your can transform your FBIK effectors to create body part-level poses. This is similar to posing your characters with IK handles. See Posing skeletons and IK handles in the Character Setup guide.

When animating with FBIK, you can key your character’s FBIK effectors and input joints to create IK animation. These keys are placed on the FBIK effectors and their FK joints, not the input skeleton’s joints. You can also key your FBIK effectors’ Reach values to set the amount of IK for your effectors. See Reach Keying Mode.

Warning Freezing the transforms of your FBIK effectors will change the position of your character and its joints in world space.

Body Parts

Each of your character’s FBIK effectors and FK joints are a member of a body part that corresponds to an existing limb or structure in your character’s body. When animating with FBIK, you can then set keys on the FBIK effectors and FK joints in a body part to animate your character’s limbs.

Body part membership

Body parts	FK joints	FBIK effectors
Hips	Hips	HipsEff
Spine	Spine Spine1-Spine9	NeckEff SpineEff
Head	Neck Neck1-Neck9 Head	HeadEff
Arms	Shoulder (clavicle) Arm (shoulder) UpArmRoll (upper arm roll) ForeArm (elbow) ForeArmRoll (lower arm roll) Hand (wrist) FingerBase	ArmEff ForeArmEff HandEff FingerBaseEff
Legs	UpLeg (hips) UpLegRoll (upper leg roll) Leg (knee) LegRoll (lower leg roll) Foot (ankle) ToeBase (ball of foot)	UpLegEff LegEff FootEff ToeBaseEff
Fingers	Each finger is a body part	Each finger tip has an effector
Toes	Each toe is a body part	Each toe tip has an effector

Character and subcharacter sets

When you add full body IK to your character, each of your character’s body parts are assigned to a subcharacter set, and all those subcharacter sets are then placed in a top-level character set. When animating with FBIK, the keys that you set on your character’s selected FBIK effectors, input joints, body parts, or the entire character are then grouped under their specific subcharacter sets.

The FBIK character set and subcharacter sets help make sure that you are keyframing the right things to keep the FBIK animation synchronized. FBIK works the best when you have synchronized keys on your character’s FBIK effectors and FK joints.

Note By default, when you selected a FBIK effector, all the keys for the selected FBIK effector’s body part are displayed in the Time Slider and its subcharacter set is loaded into the Current Character Set drop-down list. See Skeleton > Full Body IK > Body Part Autoload.

Body parts	Character or subcharacter sets
Hips	fbikCharacter
Spine	_spine
Head	_head
Arms	_leftArm / _rightArm
Legs	_leftLeg / _rightLeg
Fingers	_leftFingerThumb / _rightFingerThumb _leftFingerIndex / _rightFingerIndex _leftFingerMiddle / _rightFingerMiddle _leftFingerRing / _rightFIngerRing _leftFingerPinky / _rightFingerPinky _leftFingerExtra / _rightFingerExtra
Toes	_leftFootThumb / _rightFootThumb _leftFootIndex / _rightFootIndex _leftFootMiddle / _rightFootMiddle _leftFootRing / _rightFootRing _leftFootPinky / _rightFootPinky _leftFootExtra / _rightFootExtra

How do I pose my characters with full body IK?

To pose your character with full body IK, you need to transform your character’s FBIK effectors (for IK type behavior) and input joints (for FK type behavior) while pinning and unpinning your effectors when needed. See Pin and unpin your character’s effectors.

You can also use secondary effectors and floor contacts for your characters to aid and enhance their FBIK poses. See Create secondary effectors and Create floor contacts for your character’s hands and feet.

How do I animate my characters with full body IK?

To animate with full body IK, you need to pose your character’s body parts by translating and rotating their FBIK effectors or input joints, and then key their positions.

Warning You cannot use Autokey or the Set Key (default: S key) hotkey when animating with FBIK.

When do I set IK or FK keys?

You should set IK keys on your character when:

• You need to hold the positions of your character’s body parts during its animation’s interpolation
• You need to ensure that its body parts do not deviate from their positions at which their keys were set.

For example, keying your character’s foot placements when they contact the floor during a walk cycle. In this instance, setting IK keys on the FootEff effectors prevents undesirable foot sliding.

You should set FK keys on your character when:

• You need to release its body parts from their held positions
• You need to key its positions, but the positions do not have to be exact during its animation’s interpolation.

For example, keying your character’s FootEff effectors when its legs are off the floor swinging through the air during a walk cycle. In the instance, you need to key the movements of your character’s legs, but your character’s feet do not have stick to any one position.

How do I key my FBIK effectors and joints?

Setting the Key Mode or Reach Mode for your FBIK keys determines where your FBIK keys are placed on your character and whether your character’s FBIK animation is more FK or more IK at any given point during its animation.

When animating your character with FBIK, you can select the Key and Reach modes for your keys from the FBIK marking menu or the Animate > Set Full Body IK Keys window.

To set FBIK keys

1. Pose your character.
2. For each limb that you transformed to get to the current pose, follow steps 3 and 4.
3. Select an appropriate Reach Mode. See Reach Keying Mode.
• The IK mode sets the Reach values for your FBIK effectors to 1 and makes sure they are keyed when you set your FBIK keys. IK mode sets that your effectors are completely controlled by IK.
• The FK mode sets the Reach values for your FBIK effectors to 0 and makes sure they are keyed when you set your FBIK keys. FK mode disables your effectors’ IK; allowing the underlying FK skeleton’s joints to drive your character’s animation.
• The Simple Key mode the Reach values of the keyed FBIK effectors do not change and are not keyed.
4. Select the desired Key Mode. See Keying Mode.
• The Key Selected mode sets keys on the FK joints and FBIK effectors you select.
• The Key Body Part mode sets keys on the FBIK effector’s and FK joints of your character’s body parts.
• The Key All mode sets keys on the FBIK effectors and FK joints of your entire character.

Note FBIK works the best when you have synchronized keys on the FK skeleton and FBIK effectors. You can only set synchronized keys through the FBIK marking menu or Animate > Set Full Body IK Keys. You can set your FBIK solution’s advanced options to enhance and refine your character’s poses and animation. See hikHandle in the Character setup guide.

How do I manage my full body IK keys?

Stepped Next

There is a new tangent type called stepped next. FBIK animation keys use this new tangent type by default. This new tangent type differs from regular Stepped tangents in that its interpolation values jump immediately to that of the next key, rather than holding the value of the current key until the next key is reached. This tangent is useful because it lets you key your character’s FBIK effectors as you manipulate them, so that you do not have to plan your animation ahead or think about what is the right effector to select and manipulate to get your character into its next pose. You do not have to actively manage your FBIK animation curve tangency, as the automatically done by the FBIK system.

For example, if you used regular stepped tangents for a walk cycle that you are animating with FBIK, you would have to set keys on each joint and FBIK effector that translates or rotates as it moves from one pose to another (such as the rotations of the secondary effectors at the heels of your character’s feet or the translations of the effectors at your character’s ankles). But if you used stepped next tangents for the same FBIK animation keys, you would only have to set keys on your body parts once for each pose, not each individual FBIK effector or joint.

FBIK keys in the Time Slider

You can edit the positions and timing of your FBIK keys with the Graph Editor and Dope Sheet. However, when you need to view or delete your FBIK keys, you should use the Time Slider. Deleting your character’s FBIK keys from the Time Slider—not the Graph Editor—keeps your character’s IK and FK skeletons synchronized during its animation interpolation. Keeping your IK and FK skeletons synchronized is essential to creating good, desirable FBIK animation results. You can delete your FBIK keys from the Time Slider with the Delete FBIK Keys menu in the Time Slider context sensitive menu. See Animation controls menu in the Animation guide.

When you select a keyed FBIK effector, all its keys display in the Time Slider. But when Skeleton > Full Body IK > Body part Autoload is on, all the keys on the selected FBIK effector’s body part display in the Time Slider and the effector’s subcharacter set is automatically loaded as the Current Character.