Refining Animations

After learning the basics of the Animation Editor, you can further refine animations by calculating rotations for neighboring joints of a rig through Inverse Kinematics, or adjusting the animation easing of keyframes in the timeline.

Inverse Kinematics

Inverse kinematics (IK) helps calculate rotations for neighboring joints in order to get one specific joint to a desired location. To enable IK:

  1. Navigate to the track list, then click the IK button. The Manage IK window displays.

  2. At the bottom of the Manage IK window, click the Enable IK button.

IK Modes

There are two IK modes: Body Part and Full Body.

You can toggle between both IK modes at the top of the Manage IK window.

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Body Part

In Body Part mode, which is exclusive to R15 rigs, when you move one part, only related parts change to achieve that movement. Studio determines the set of related parts by sectioning off unrelated limbs.

For example, if you move the RightHand part, only the related parts (RightHand, RightLowerArm, and RightUpperArm) adjust to fulfill that motion, while every other unrelated limb (LeftUpperArm, LeftUpperLeg, and RightUpperLeg) remains static.

Body Part mode limits movement to related parts

Full Body

In Full Body mode, when you move one part, all parts move with it. However, if you pin a part, that part will not move. For example, if you pin the LeftFoot part and drag the LeftHand part, all parts between them will adjust to move the hand relative to the foot, including the RightUpperLeg and its related parts, RightUpperArm and its related parts, LowerTorso, LeftUpperLeg and the LeftLowerLeg part.

Full Body mode moves all parts through inverse kinematics

You can pin as many parts as you like, and when you move a part, the IK system does its best to satisfy all of those constraints at once.

Pinning Parts

When editing an animation in Full Body IK mode, you can pin a part to make it immovable. In the following video, the right foot is pinned and remains stationary while moving other parts, but the pinned foot can still be directly manipulated.

Pinning locks a part in place while other parts move through inverse kinematics

To pin a specific part:

  1. Navigate to the Manage IK window and select the Full Body IK mode.

  2. Find the part that you want to pin, then click the pin icon next to its name.

When you move any other part of the rig, the pinned part will remain in the same position while the other parts move around it.

Animation Easing

For each keyframe in the Animation Editor, you can choose both an easing style and an easing direction.

Easing Style

Easing style is the rate at which an animation moves between different frame positions within the animation. By default, a part will move and/or rotate from one keyframe to the next in an even, steady motion known as linear easing. In the following video, linear easing makes the character's turning animation appear stiff and robotic.

Linear easing

While that may look appropriate for some motions, compare the following video where cubic easing makes the animation of the character's motion appear more natural.

Cubic easing

To change the easing style for one or more keyframes:

  1. Navigate to the timeline and select one or more keyframes. Every selected keyframe is now surrounded by a blue border.

  2. Right-click on a keyframe with a border. A pop-up menu displays.

  3. Hover over Easing Style, then choose from the following options:

    • Linear - Moves at a constant speed.
    • Constant - Removes interpolation between the selected keyframe and next keyframe. The animation will "snap" from keyframe to keyframe.
    • Cubic - Eases in or out with cubic interpolation.
    • Elastic - Moves as if the object is attached to a rubber band.
    • Bounce - Moves as if the start or end position of the tween is bouncy.

Easing Direction

Easing direction defines which end of the animation movement is affected by the easing style. By default, the motion is slower at the beginning and faster toward the end of the animation.

To change the easing direction for one or more keyframes:

  1. Navigate to the timeline and select one or more keyframes. Every selected keyframe is now surrounded by a blue border.

  2. Right-click on a keyframe with a border. A pop-up menu displays.

  3. Hover over Easing Direction, then choose from the following options:

    • Out - The motion will be faster at the beginning and slower toward the end.
    • InOut - In and Out on the same tween, with In at the beginning and Out taking effect halfway through.
    • In - The motion will be slower at the beginning and faster toward the end.