Threejs Animation

When to use this skill

ALWAYS use this skill when the user mentions:

• AnimationMixer.update, AnimationAction play/pause/stop, crossfade, synchronized clips
• AnimationClip from glTF or AnimationClipCreator, retargeting caveats at API level
• Keyframe tracks: position/rotation/scale/color tracks, boolean/string tracks where applicable
• IK: CCDIKSolver / CCDIKHelper from addons

IMPORTANT: animation vs objects

• threejs-animation = time evaluation and tracks.
• threejs-objects = SkinnedMesh/Skeleton attachment, bind pose—mesh side.

Trigger phrases include:

• "AnimationMixer", "AnimationAction", "AnimationClip", "crossFade", "KeyframeTrack"
• "动画混合", "骨骼动画", "剪辑", "淡入淡出"

How to use this skill

1. Collect clips from gltf.animations or create with utilities / AnimationClipCreator.
2. Create mixer bound to root object (often scene or rig root).
3. Create actions per clip via mixer.clipAction(clip); configure loop mode (LoopOnce, LoopRepeat, LoopPingPong).
4. Per frame: compute delta seconds (use Clock from core—documented under Core in docs index), call mixer.update(delta).
5. Blending: adjust weight, crossFadeTo, enabled flags; watch for additive vs full replacement semantics per docs.
6. PropertyBinding: understand path strings targeting bones/morphs—errors often from wrong object names.
7. IK addon: attach solver after base animation if using CCD IK from examples.

See examples/workflow-mixer-action.md.

Doc map (official)

More: references/official-sections.md.

Scope

• In scope: Core Animation module, keyframe pipeline, listed addons for clip creation and IK.
• Out of scope: DCC export best practices; physics ragdoll; audio sync (link conceptually only).

Common pitfalls and best practices

• Forgetting mixer.update freezes animation; double update per frame speeds up.
• Mixing clips with incompatible hierarchies causes violent pops—validate bind pose.
• Root motion must be handled in game logic if not baked—document explicitly.
• Large track counts cost CPU—strip unused tracks in preprocessing when possible.

Documentation and version

Behavior of AnimationMixer, tracks, and glTF animation import can change between three.js majors. Treat the Animation section of the docs index as authoritative for the user’s installed version; when upgrading, check the three.js repository release notes and migration notes for renamed properties or loader output.

Agent response checklist

When answering under this skill, prefer responses that:

1. Cite the exact class (AnimationMixer, AnimationAction, etc.) or addon (CCDIKSolver) from the official docs.
2. Include at least one https://threejs.org/docs/... link (e.g. AnimationAction).
3. Relate clips to SkinnedMesh / skeleton via threejs-objects when deformation is involved.
4. Mention mixer.update(delta) and a stable time source (Clock) explicitly.
5. Reference official examples by name only (no full file paste).

References

• https://threejs.org/docs/#Animation
• https://threejs.org/docs/AnimationMixer.html
• https://threejs.org/docs/AnimationAction.html
• https://threejs.org/docs/PropertyBinding.html

Keywords

English: animationmixer, animationaction, animationclip, keyframetrack, crossfade, skinning, propertybinding, three.js

中文： 动画混合、AnimationMixer、AnimationAction、关键帧、骨骼动画、剪辑、淡入淡出、three.js

能力边界

✅ 适用场景

• 当你需要使用此技能对应的技术栈时
• 当项目需要遵循最佳实践时
• 当需要快速上手或深入理解核心概念时

⚠️ 需要注意

• 复杂业务逻辑需要结合具体场景调整
• 性能优化需要根据实际数据量评估

❌ 不适用场景

• 不相关的技术栈或框架
• 需要完全自定义的特殊场景

常见陷阱 (Gotchas)

1. 版本兼容性：注意框架版本与依赖库的兼容性，不同版本 API 可能有差异
2. 配置文件格式：配置文件格式错误是最常见的问题，建议使用编辑器的语法检查
3. 环境变量：确保所有必要的环境变量已正确设置，敏感信息不要硬编码
4. 依赖冲突：多版本共存时注意依赖冲突，使用 lock 文件锁定版本
5. 性能陷阱：大数据量场景下注意性能优化，避免 N+1 查询等常见问题

使用流程

Step 1: 环境准备

确保开发环境已安装必要的依赖和工具。

Step 2: 配置初始化

根据项目需求进行基础配置。

Step 3: 核心功能使用

按照示例代码实现核心功能。

Step 4: 测试验证

运行测试确保功能正常。

Step 5: 部署上线

完成开发后进行部署和监控。