# 3d Sky Background

Create a camera-correct sky background for a 3D scene with a procedural atmosphere or...

- Repository: https://github.com/MengTo/Skills (7170 stars)
- Category: Media
- License: MIT
- Last updated: 2026-11-01
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add MengTo/Skills --skill 3d-sky-background -g -a claude-code -y`
Codex: `npx skills add MengTo/Skills --skill 3d-sky-background -g -a codex -y`
Cursor: `npx skills add MengTo/Skills --skill 3d-sky-background -g -a cursor -y`
Gemini CLI: `npx skills add MengTo/Skills --skill 3d-sky-background -g -a gemini-cli -y`

## Description

Create a camera-correct sky background for a 3D scene with a procedural atmosphere or panorama, horizon haze, aligned sunlight, and coherent environment lighting. Use for architectural skies, outdoor 3D backgrounds, golden hour, and day-to-night sky transitions.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# 3D Sky Background

Build a sky that surrounds the world, with a readable horizon and lighting that belongs to the same atmosphere.

## Choose the representation

Inspect the project's renderer, camera range, color pipeline, environment lighting, and existing assets. Use an existing licensed panorama when its cloud composition matters, a procedural sky when changing sun position matters, or a restrained hybrid. Keep the project's rendering backend and version; do not add a second renderer for the sky.

Keep three responsibilities explicit: the visible sky background, the reflection/ambient environment, and direct sun lighting. A background photograph alone does not light PBR objects. A PMREM environment does not supply a shadow-casting directional sun. See the [PMREM documentation](https://threejs.org/docs/pages/PMREMGenerator.html).

## Build a stable surrounding sky

- Use the engine's background facility, a fullscreen direction shader, or an inward-facing dome with depth writes disabled and fog disabled. A dome must fit inside the camera's clipping range and follow camera translation; it should retain world orientation as the camera rotates.
- Derive color from the normalized viewing direction. Blend a pale warm horizon through a muted middle band into a cooler zenith. Keep the lower hemisphere compatible with the ground haze rather than leaving an exposed hard edge.
- Use a shared sun direction for the visible disk, glow, directional light, and any sky-ray pass. A broad halo and a small disk are separate terms; avoid a large white blob.
- Add distant silhouettes only when the composition needs depth. Keep them low contrast, with a hue and value close to the horizon.

## Map a panorama deliberately

A true equirectangular sky wraps a full 360° horizontally and 180° vertically. Establish a consistent world-axis convention, rotate the texture so its photographed sun matches the scene sun, and inspect both the seam and zenith.

The rest: https://github.com/MengTo/Skills/blob/HEAD/agent-skills/3d/3d-sky-background/SKILL.md