# Threejs Helpers

> Debug and visualization helpers in three.js Core Helpers (AxesHelper, GridHelper, CameraHelper, light helpers, SkeletonHelper, bounding box helpers, PlaneHelper, PolarGridHelper, ArrowHelper) and Addons Helpers (VertexNormalsHelper, VertexTangentsHelper, RectAreaLightHelper, LightProbeHelper, ViewHelper, OctreeHelper, TextureHelper, PositionalAudioHelper, AnimationPathHelper, RapierHelper). Use only for development and editor overlays—not for shipping art; for gizmo-style manipulation use threejs-controls.

- Skill: `full-stack-skills/threejs-helpers` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add full-stack-skills/threejs-helpers`
- Raw SKILL.md: https://api.skillmd.com/api/skills/full-stack-skills/threejs-helpers/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: full-stack-skills (https://skillmd.com/u/full-stack-skills)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/full-stack-skills/threejs-helpers

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## When to use this skill

**ALWAYS use this skill when the user mentions:**

- Visualizing axes, grids, camera frusta, shadow cameras, light directions
- Showing skeleton bones, bounding boxes, normals/tangents for mesh inspection
- Light probe or rect area visualization via helper classes

**IMPORTANT: helpers vs production meshes**

- Helpers are **debug** objects; do not use as final scene geometry.

**Trigger phrases include:**

- "AxesHelper", "GridHelper", "CameraHelper", "SkeletonHelper", "VertexNormalsHelper"
- "辅助线", "法线显示", "包围盒调试"

## How to use this skill

1. **Attach** helper to the object it describes (e.g., `CameraHelper(light.shadow.camera)`).
2. **Update** when targets move—some helpers need per-frame refresh.
3. **Remove** in production builds or behind debug flags.
4. **Performance**: helpers add draw calls—disable when profiling performance issues.
5. **Addons**: import from `three/addons/helpers/...` paths per **threejs-dev-setup**.

See [examples/workflow-light-camera-helpers.md](examples/workflow-light-camera-helpers.md).

## Doc map (official)

| Docs section | Representative links |
|--------------|----------------------|
| Helpers | https://threejs.org/docs/AxesHelper.html |
| Helpers | https://threejs.org/docs/GridHelper.html |
| Helpers | https://threejs.org/docs/CameraHelper.html |
| Helpers | https://threejs.org/docs/SkeletonHelper.html |

## Scope

- **In scope:** Core + Addons helpers for visualization.
- **Out of scope:** Production meshes or shipping art (**threejs-geometries**, **threejs-lights**); orbit/transform gizmo behavior (**threejs-controls**); editor UX parity with DCC tools; physics debug beyond helper stubs.

## Common pitfalls and best practices

- Too many helpers obscures view—toggle per subsystem.
- Wrong attachment parent misaligns helper transforms.
- Helpers inherit scene graph transforms—parent under a debug group to batch hide/show.
- Some helpers duplicate geometry cost; strip in production or use `#ifdef DEBUG` style flags.
- `CameraHelper` for shadow cameras must reference `light.shadow.camera`, not the main view camera.

## Documentation and version

Helpers are listed under [Helpers](https://threejs.org/docs/#Helpers) (core) and **Addons → Helpers** in [three.js docs](https://threejs.org/docs/). They are for **debug** only; production meshes and lighting should use real geometry/lights (**threejs-geometries**, **threejs-lights**).

## Agent response checklist

When answering under this skill, prefer responses that:

1. Link the helper class (`AxesHelper`, `CameraHelper`, …) being used.
2. State that helpers are not shipping art—strip or gate behind debug flags.
3. Pair shadow/light helpers with **threejs-lights** tuning workflows.
4. Mention performance cost when many helpers are enabled.
5. Import paths follow **threejs-dev-setup** addon conventions.

## References

- Manual (debug workflow context): https://threejs.org/manual/
- Docs index (Helpers group): https://threejs.org/docs/#Helpers
- Examples: https://threejs.org/docs/DirectionalLightHelper.html

## Keywords

**English:** helper, debug, axes, grid, skeleton, normals, light helper, three.js

**中文：** 辅助、调试、坐标轴、网格、骨架、法线、Helper、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。