lottie-bodymovin（洛蒂·身体移动）

Lottie Animation Principles

Implement all 12 Disney animation principles using Lottie (Bodymovin) for vector animations.

1. Squash and Stretch

In After Effects before export:

• Animate Scale X and Y inversely
• Use expression: s = transform.scale[1]; [100 + (100-s), s]

// Control at runtime
lottie.setSpeed(1.5); // affect squash timing

2. Anticipation

Structure your AE composition:

1. Frames 0-10: Wind-up pose
2. Frames 10-40: Main action
3. Frames 40-50: Settle

// Play anticipation segment
anim.playSegments([0, 10], true);
setTimeout(() => anim.playSegments([10, 50], true), 200);

3. Staging

// Layer multiple Lotties
<div className="scene">
  <Lottie animationData={background} style={{ opacity: 0.6 }} />
  <Lottie animationData={hero} style={{ zIndex: 10 }} />
</div>

4. Straight Ahead / Pose to Pose

Pose to pose in AE:

• Set keyframes at key poses
• Let AE interpolate between
• Use Easy Ease for smoothing

// Jump to specific poses
anim.goToAndStop(25, true); // frame 25

5. Follow Through and Overlapping Action

In After Effects:

• Offset child layer keyframes by 2-4 frames
• Use parenting with delayed expressions
• thisComp.layer("Parent").transform.position.valueAtTime(time - 0.05)

6. Slow In and Slow Out

AE Keyframe settings:

• Select keyframes > Easy Ease (F9)
• Use Graph Editor to adjust curves
• Bezier handles control acceleration

// Adjust playback speed dynamically
anim.setSpeed(0.5); // slower
anim.setSpeed(2); // faster

7. Arc

In After Effects:

• Use motion paths (position property)
• Convert keyframes to Bezier
• Pull handles to create arcs
• Or use "Auto-Orient to Path"

8. Secondary Action

// Trigger secondary animation
mainAnim.addEventListener('complete', () => {
  secondaryAnim.play();
});

// Or sync with frame
mainAnim.addEventListener('enterFrame', (e) => {
  if (e.currentTime > 15) particleAnim.play();
});

9. Timing

anim.setSpeed(0.5);  // half speed - dramatic
anim.setSpeed(1);    // normal
anim.setSpeed(2);    // double speed - snappy

// Or control frame rate in AE export
// 24fps = cinematic, 30fps = smooth, 60fps = fluid

10. Exaggeration

In After Effects:

• Push scale beyond 100% (120-150%)
• Overshoot rotation
• Use Overshoot expression
• amp = 15; freq = 3; decay = 5; n = 0; time_start = key(1).time; if (time > time_start) {n = (time - time_start) / thisComp.frameDuration; amp * Math.sin(freq*n) / Math.exp(decay*n/100);} else {0;}

11. Solid Drawing

In After Effects:

• Use 3D layers
• Apply perspective camera
• Animate Z position and rotation
• Use depth of field

12. Appeal

Design principles in AE:

• Smooth curves over sharp angles
• Consistent timing patterns
• Pleasing color palette
• Clean vector shapes

// React Lottie with hover
<Lottie
  animationData={data}
  onMouseEnter={() => anim.setDirection(1)}
  onMouseLeave={() => anim.setDirection(-1)}
/>

Lottie Implementation

import Lottie from 'lottie-react';
import animationData from './animation.json';

<Lottie
  animationData={animationData}
  loop={true}
  autoplay={true}
  style={{ width: 200, height: 200 }}
/>

Key Lottie Features

• playSegments([start, end]) - Play frame range
• setSpeed(n) - Control timing
• setDirection(1/-1) - Forward/reverse
• goToAndStop(frame) - Pose control
• addEventListener - Frame events
• Interactivity via lottie-interactivity