Bone3 Skeletal AnimationBone3 Skeletal Animationbone3.com
中
Choose an article

Animation

Easing Presets, Bezier Curves, and Loop Seams

Control the speed from a starting key to the next segment and fix jumps in looping animations.

IntermediateAbout 18 minFor Editor v1.0 · Tutorial updated Oct 26, 2026
Download the sample PSD

After this article

Choose appropriate easing and improve motion rhythm through curves and matching endpoint poses.

01

Set easing on the transition's starting key

Easing is set on the starting key and controls interpolation to the next segment. Select that start key before choosing a curve, not just the ending key.

TypeMotion feelCommon use
LinearConstant speedMechanical movement and uniform translation
Ease inSlow to fastStarts, acceleration, and falling over
Ease outFast to slowLandings, returns, and stops
Ease in-outGentle at both endsIdle, swaying, and general transitions
StepHold, then jumpSwitches and instant changes
Elastic / backOvershoot or reboundImpact and cartoon accents
Custom BezierManually controlled tangentsTransitions that need a precise speed curve
  1. 1

    Select the starting key

    Click the key at the beginning of the transition. Easing actions become available.

    Expected resultThe selection has the intended object, property, and starting frame.

  2. 2

    Apply a preset and play

    Choose Linear, Ease In, Ease Out, or another preset and play the interval repeatedly. Change one segment at a time.

    Expected resultThe starting key stores the easing used by the next segment, with a noticeable rhythm change.

    Select the transition's start key before applying easing. This shows the controls and a real key, not proof that a curve has been applied.
02

Edit a custom Bezier curve

  1. 1

    Open the curve editor

    Double-click the selected starting key or choose Custom Bezier.

    Expected resultThe Bezier curve editor opens.

    Double-click the starting key or choose Custom Bezier to enter curve editing. This image locates the entry, not a completed curve edit.
  2. 2

    Adjust the curve and anchors

    Drag control points to change acceleration. Double-click the curve to insert an anchor or an existing anchor to delete it. Reset when you need to start over.

    Expected resultThe curve has the intended shape and no other track is changed accidentally.

  3. 3

    Confirm and verify in the animation

    Confirm, then play this transition and its neighbors. Curves change timing; they cannot fix incorrect endpoint poses.

    Expected resultAcceleration and deceleration feel natural without introducing a new jump.

03

Fix a loop seam

  1. Compare first and last bone angles, positions, image deformation, and IK targets. Fix mismatched poses first.
  2. Check the direction of motion across the last-to-first transition to avoid sudden reversals or stops.
  3. Inspect foot and weapon draw order and any attachment switch that appears on only one keyframe.
  4. Adjust easing near the endpoints last instead of immediately adding many in-between keys.
Diagnose loops using the picture, keys, and curves together.