threejs-scenes

## When to use this skill **ALWAYS use this skill when the user mentions:** - `Scene` as root, `scene.background`, environment or skyball setup at scene level - `Fog` or `FogExp2` parameters (`near`, `far`, `color`, density) and interaction with camera far plane - Organizing render lists conceptually (children of scene) **IMPORTANT: scenes vs textures vs loaders** | Concern | Skill | |---------|--------| | Scene + fog API | **threejs-scenes** | | Texture sampling, PMREM generator usage | **threejs-textures** | | Fetching HDR/glTF | **threejs-loaders** | **Trigger phrases include:** - "Scene", "Fog", "FogExp2", "background", "雾" - "场景根节点", "线性雾", "指数雾" ## How to use this skill 1. Instantiate `Scene` and add lights/meshes/cameras as children per graph rules (**threejs-objects**). 2. Choose fog: linear `Fog` vs exponential `FogExp2` for outdoor/horizon feel. 3. Tune fog `near`/`far` alongside camera `far` to avoid clipping artifacts. 4. Set `scene.background` to `Color`, `Texture`, or cube map per docs; env lighting still needs matching renderer/material settings. 5. When user wants IBL from HDR file, point to loaders → textures → materials pipeline explicitly. 6. Document that fog does not replace frustum culling for performance. See [examples/workflow-fog-background.md](examples/workflow-fog-background.md). ## Doc map (official) | Docs section | Representative links | |--------------|----------------------| | Scenes | https://threejs.org/docs/#Scenes | | Scenes | https://threejs.org/docs/Scene.html | | Fog | https://threejs.org/docs/Fog.html | | FogExp2 | https://threejs.org/docs/FogExp2.html | ## Scope - **In scope:** `Scene`, fog types, background field semantics at API level. - **Out of scope:** HDR / glTF file fetch (**threejs-loaders**); PMREM and texture sampling (**threejs-textures**); tone mapping / output color space defaults (**threejs-renderers**); full-screen fog-only post stack (**threejs-postprocessing**) unless tying to scene `Fog`; custom atmospheric scattering shaders beyond core fog API. ## Common pitfalls and best practices - Fog color should harmonize with background to hide the horizon seam. - Very large `far` on camera with fog still needs scene scale consistency. - `background` rotation/intensity features depend on renderer version—cite current docs. ## Documentation and version `Scene`, `Fog`, and background fields are documented under [Scenes](https://threejs.org/docs/#Scenes) in [three.js docs](https://threejs.org/docs/). Environment-related visuals often combine this skill with **threejs-textures** (PMREM) and **threejs-loaders** (HDR files)—link those pages when the user moves from “fog color” to “HDR sky”. ## Agent response checklist When answering under this skill, prefer responses that: 1. Link `Scene`, `Fog`, or `FogExp2` official pages. 2. Relate fog distances to **threejs-camera** `far` plane and world scale. 3. Defer PMREM/HDR file steps to **threejs-textures** / **threejs-loaders** with one sentence each. 4. Avoid duplicating full color-management tutorials—point to renderer + textures skills. ## References - https://threejs.org/docs/Scene.html - https://threejs.org/docs/Fog.html - https://threejs.org/docs/FogExp2.html ## Keywords **English:** scene, fog, fogexp2, background, environment, three.js **中文：** 场景、雾、Fog、背景、环境、three.js