threejs-helpers

---
name: "threejs-helpers"
description: "ALWAYS use this skill when the user mentions:"
license: "BSD-2-Clause"
---

## 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。