Build Three.js Scroll Worlds

Build one detailed real-time world and use native document scroll as its deterministic conductor. Keep the renderer, scene graph, and spatial continuity alive while camera composition, light, fog, animation, copy, and interaction focus move through authored chapters.

The mechanism is one persistent Three.js world + one normalized reversible scroll state. If removing either makes the experience collapse into stacked sections, this skill applies.

The exact Kage demo proves the quality bar; it is staging, not a mandatory subject or layout. Use its detailed anatomy only when the requested direction benefits from it: references/kage-anatomy.md.

Route the request correctly

• Use threejs for a single interactive scene with no scroll-authored journey.
• Use scroll-world-storytelling when deciding between real-time 3D, pre-rendered video, and DOM-first storytelling.
• Use scroll-scrubbed-visual-sequence for a video or image sequence whose time is scrubbed by scroll.
• Use cinematic-scroll-storytelling for DOM-first GSAP/Lenis choreography.
• Use this skill when objects must remain truly spatial and interactive while scroll moves through several compositions in one live WebGL world.

Do not disguise a video as Three.js. The public oso95/scroll-world project, reviewed at commit 71cc36d, is a strong reference for intake, scene ledgers, budget gates, mobile-specific composition, config-driven playback, and seam QA, but its renderer is a pre-generated video chain. This skill adopts those structural strengths while retaining real geometry, materials, lighting, raycasting, and camera control.

Read the build references