threejs-loaders

When to use this skill

ALWAYS use this skill when the user mentions:

• GLTFLoader, DRACOLoader, KTX2Loader, FBXLoader, OBJLoader, progress and error handling
• LoadingManager for global progress, Cache for HTTP caching control
• Export: GLTFExporter, OBJExporter, HDR/KTX2 export pipelines
• IES, UltraHDR, or domain-specific loaders listed under Addons Loaders in docs

IMPORTANT: loaders vs textures

• threejs-loaders = fetch/decode/parse files into three objects.
• threejs-textures = Texture/DataTexture parameters, sampling, PMREM after you already have image buffers.

IMPORTANT: loaders vs dev-setup

• Import path issues belong to threejs-dev-setup; this skill assumes imports resolve.

Trigger phrases include:

• "GLTFLoader", "DRACO", "KTX2", "LoadingManager", "export gltf"
• "加载模型", "导出", "进度条"

How to use this skill

1. Pick loader by format; prefer glTF for PBR interchange when possible.
2. Wire LoadingManager for multi-asset batches; surface onStart/onLoad/onProgress/onError.
3. glTF + Draco: instantiate DRACOLoader, set decoder path, attach to GLTFLoader.setDRACOLoader per current docs.
4. glTF + KTX2: configure KTX2Loader with transcoder path and connect to GLTFLoader when using Basis textures.
5. Export: use GLTFExporter with options matching round-trip needs; note large scenes and binary vs JSON.
6. Security: only load user URLs with validation; mention CORS for cross-origin assets.
7. After load: traverse scene for materials/meshes—hand off material tuning to threejs-materials.

See examples/workflow-gltf-draco.md.

Doc map (official)

Extended list: references/official-sections.md.

Scope

• In scope: Loader and exporter classes, manager/cache, format choice, plugin wiring for Draco/KTX2, export basics.
• Out of scope: Server-side transcoding pipelines; physics or game engine asset tooling outside three docs.

Common pitfalls and best practices

• Draco/KTX2 decoder paths must match deployed files; broken paths fail silently until onError surfaces.
• Duplicate texture instances after merge—consider renderer.initTexture implications when cloning materials.
• Exporters may not round-trip custom shaders; document limitations.
• Always dispose geometries/materials when replacing loaded scenes to avoid GPU leaks.

Documentation and version

Loader and exporter APIs (especially GLTFLoader + DRACOLoader / KTX2Loader wiring) change between three.js versions. Follow Loaders and Addons → Loaders / Exporters in three.js docs; decoder WASM paths are deployment-specific, not library-version alone.

Agent response checklist

When answering under this skill, prefer responses that:

1. Link LoadingManager, GLTFLoader, or the relevant format page on https://threejs.org/docs/.
2. Separate loading (this skill) from texture/material tuning after decode (threejs-textures, threejs-materials).
3. Document Draco/KTX2 decoder path and CORS when assets fail silently.
4. Mention exporter limitations (custom shaders, extensions) honestly.
5. Encourage dispose() when replacing entire loaded scenes.

References

• https://threejs.org/docs/#Loaders
• https://threejs.org/docs/LoadingManager.html
• https://threejs.org/docs/GLTFLoader.html
• https://threejs.org/docs/GLTFExporter.html

Keywords

English: gltf, gltfloader, dracoloader, ktx2, loadingmanager, cache, exporter, asset pipeline, three.js

中文： GLTFLoader、加载器、Draco、KTX2、导出、资源、进度、three.js