Image to Three.js Model
img2threejs/img2threejs
Rebuilds the object in a reference image as a procedural, animation-ready Three.js model written entirely in code, using staged sculpting with quality checks.
Add sun shafts and crepuscular rays to a Three.js or equivalent 3D scene, using scene occlusion, a projected sun position, controlled foreground spill, and scalable post-processing.
Install 3D Sky Rays
$ npx skills add MengTo/Skills --skill 3d-sky-rays -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install MengTo/Skills 3d-sky-rays --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/MengTo/Skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/agent-skills/3d/3d-sky-rays .claude/skills/3d-sky-rays && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "3d-sky-rays" agent skill from https://github.com/MengTo/Skills/tree/main/agent-skills/3d/3d-sky-rays into .claude/skills/3d-sky-rays/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "3d-sky-rays", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/MengTo/Skills/tree/main/agent-skills/3d/3d-sky-raysType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add MengTo/Skills --skill 3d-sky-rays -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install MengTo/Skills 3d-sky-rays --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/MengTo/Skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/agent-skills/3d/3d-sky-rays .agents/skills/3d-sky-rays && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "3d-sky-rays" agent skill from https://github.com/MengTo/Skills/tree/main/agent-skills/3d/3d-sky-rays into .agents/skills/3d-sky-rays/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "3d-sky-rays", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add MengTo/Skills --skill 3d-sky-rays -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install MengTo/Skills 3d-sky-rays --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/MengTo/Skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/agent-skills/3d/3d-sky-rays .cursor/skills/3d-sky-rays && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "3d-sky-rays" agent skill from https://github.com/MengTo/Skills/tree/main/agent-skills/3d/3d-sky-rays into .cursor/skills/3d-sky-rays/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "3d-sky-rays", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/MengTo/Skills.git --path agent-skills/3d/3d-sky-rays--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add MengTo/Skills --skill 3d-sky-rays -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install MengTo/Skills 3d-sky-rays --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/MengTo/Skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/agent-skills/3d/3d-sky-rays .gemini/skills/3d-sky-rays && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "3d-sky-rays" agent skill from https://github.com/MengTo/Skills/tree/main/agent-skills/3d/3d-sky-rays into .gemini/skills/3d-sky-rays/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "3d-sky-rays", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install MengTo/Skills 3d-sky-raysInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add MengTo/Skills --skill 3d-sky-rays -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/MengTo/Skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/agent-skills/3d/3d-sky-rays .github/skills/3d-sky-rays && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "3d-sky-rays" agent skill from https://github.com/MengTo/Skills/tree/main/agent-skills/3d/3d-sky-rays into .github/skills/3d-sky-rays/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "3d-sky-rays", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add MengTo/Skills --skill 3d-sky-rays -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install MengTo/Skills 3d-sky-rays --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/MengTo/Skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/agent-skills/3d/3d-sky-rays .opencode/skills/3d-sky-rays && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "3d-sky-rays" agent skill from https://github.com/MengTo/Skills/tree/main/agent-skills/3d/3d-sky-rays into .opencode/skills/3d-sky-rays/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "3d-sky-rays", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
3d-sky-rays- GitHub stars
- 6.6k
- Token cost
- ~1.2k tokens
- SKILL.md length
- 623 words
- Files
- 3
- Skills in repo
- 39
- Repo updated
- First seen
- Licence
- MIT
At a glance
Add sun shafts and crepuscular rays to a Three.js or equivalent 3D scene, using scene occlusion, a projected sun position, controlled foreground spill, and scalable post-processing.
- Works in 6 steps: Render scene color in linear HDR. Obtain… → A dedicated sky mask is the portable… → Project a point along the sun direction… → …
- Rays of light from the sky
- SKILL.md covers Fit the existing renderer, Build an occlusion-aware ray…, Tune appearance before cost and Verify, plus 1 more section
- Calls uv
What it does
3D Sky Rays is an agent skill from MengTo/Skills. Add sun shafts and crepuscular rays to a Three.js or equivalent 3D scene, using scene occlusion, a projected sun position, controlled foreground spill, and scalable post-processing. Use for rays of light from the sky, sunlight through trees or roofs, and golden-hour architectural scenes.
Its SKILL.md is about 1.2k tokens, which your agent loads only when the skill is triggered. The skill folder holds 3 other files (for example `REFERENCES.md` and `agents/openai.yaml`).
It sits in Game Development, covering 3D graphics and WebGL. It works with Three.js. The repository describes itself as: Agent skills for designers and builders using Codex, Claude, Cursor, and other AI coding agents. The licence is MIT.
When your agent uses it
- Rays of light from the sky
- Sunlight through trees
- Golden-hour architectural scenes
Example prompts
- “/3d-sky-rays”
Workflow steps
6 steps, taken from the first numbered list in SKILL.md.
- Render scene color in linear HDR. Obtain a mask identifying open sky: white for sky, black for opaque occluders. Match foliage alpha…
- A dedicated sky mask is the portable default. Reusing scene alpha is an optimization only when every preceding pass preserves its meaning…
- Project a point along the sun direction from the camera. Reject a source behind the camera before using projected coordinates. Convert NDC…
- For each ray-buffer pixel, march toward the sun UV. Sample sky visibility multiplied by sky brightness above an HDR threshold. Accumulate…
- Reject UVs outside the mask texture. Fade the effect as the sun moves far off-screen; clamping samples to the edge creates bright bands. A…
- Composite the ray color additively into linear scene color before the final tone-map/output transform. Preserve the input alpha if later…
What it can do on your machine
Read from SKILL.md and the folder at commit 83a47fe. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
uv
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md. Its commands use uv, which can reach the network depending on how they are called.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
3D Sky Rays loads about 1.2k tokens when it runs. Until then it costs about 75 tokens; SKILL.md has 623 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from MengTo/Skills at commit 83a47fe, republished under its MIT licence (© MengTo). 623 words, ~1,229 tokens.
Download SKILL.mdSave it as
.claude/skills/3d-sky-rays/SKILL.md (or your agent's skills folder). This skill also uses 2 other files; get the full folder from GitHub.- name
- 3d-sky-rays
- description
- Add sun shafts and crepuscular rays to a Three.js or equivalent 3D scene, using scene occlusion, a projected sun position, controlled foreground spill, and scalable post-processing. Use for rays of light from the sky, sunlight through trees or roofs, and golden-hour architectural scenes.
3D Sky Rays
Make the light appear to travel through gaps in the scene. Roof edges and foliage should shape the shafts as the camera moves.
Fit the existing renderer
Inspect the renderer version, render targets, alpha usage, depth path, tone mapping, and post-processing order. Keep the existing WebGL or WebGPU backend. The shader recipe below describes a WebGL screen-space effect; implement the equivalent in the project's node/render pipeline when using WebGPU.
Use one normalized world-space direction pointing toward the sun for the sky, ray source, and directional lighting. If the art direction deliberately offsets the visible sun from the lighting sun, document and control that offset in one place.
Build an occlusion-aware ray pass
- Render scene color in linear HDR. Obtain a mask identifying open sky: white for sky, black for opaque occluders. Match foliage alpha cutouts and vertex motion in the mask pass so leaves do not become solid rectangles.
- A dedicated sky mask is the portable default. Reusing scene alpha is an optimization only when every preceding pass preserves its meaning: sky alpha 0, opaque geometry alpha 1. Transparent glass, particles, canvas compositing, and AO can break that convention; inspect the mask directly.
- Project a point along the sun direction from the camera. Reject a source behind the camera before using projected coordinates. Convert NDC to UV with
uv = ndc.xy * 0.5 + 0.5; account for the pipeline's texture orientation. - For each ray-buffer pixel, march toward the sun UV. Sample sky visibility multiplied by sky brightness above an HDR threshold. Accumulate decaying samples and divide by the sum of weights so sample-count changes do not change exposure.
- Reject UVs outside the mask texture. Fade the effect as the sun moves far off-screen; clamping samples to the edge creates bright bands. A small overscan margin is useful for a sun just outside the frame.
- Composite the ray color additively into linear scene color before the final tone-map/output transform. Preserve the input alpha if later passes need it.
Core accumulation, expressed as pseudocode:
step = (pixelUV - sunUV) * density / sampleCount
sampleUV = pixelUV - step * jitter
sum = 0; weightSum = 0; weight = 1
repeat sampleCount times:
sampleUV -= step
if sampleUV is inside the texture:
energy = max(luminance(scene(sampleUV)) - threshold, 0)
sum += min(energy, energyCap) * skyMask(sampleUV) * weight
weightSum += weight
weight *= decay
rays = sum / max(weightSum, epsilon)Use aspect-correct distance from the source for radial falloff. Keep any angular variation broad and subtle; the scene occlusion should provide most of the structure. On opaque foreground surfaces, attenuate the screen-space overlay strongly so wood and stone retain contrast. This is an artistic approximation, not a substitute for depth-integrated volumetric scattering.
Show full SKILL.md (233 more words)Show less
Tune appearance before cost
Start with a low sun, warm neutral tint, visible gaps, and restrained intensity. View from behind a roofline and through a canopy. Whiteout usually means excessive intensity or a bad mask, not insufficient bloom.
Use roughly 24–48 samples and a half-resolution ray buffer as a starting experiment; increase only when visible banding warrants it. Seijaku's reference uses 72 samples, which is a reference choice rather than a required quality floor. Smooth noise jitter can reduce bands, but animated jitter can shimmer; use stable noise for still or reduced-motion views unless temporal accumulation is available.
Skip the pass when its contribution is zero. Resize its buffers with the drawing buffer, dispose replaced targets, and measure its incremental GPU/frame cost with rays enabled and disabled. Avoid synchronous GPU readback in the render loop.
Verify
- Roofs and leaf silhouettes visibly interrupt shafts; no rectangular foliage halos.
- Turning away from the sun removes the effect without a mirrored source or flash.
- Entering an interior preserves surface contrast; unrelated emissive objects do not become suns.
- Camera orbit, portrait resize, dusk, and a static reduced-motion frame remain stable.
- Desktop and mobile checks include shader errors, frame time, and the actual ray-buffer size.
Reference
Read REFERENCES.md for the source and renderer documentation. In Seijaku, inspect GodRayShader, makePost, and the projected-source update. Its alpha-mask convention depends on its complete render pipeline; do not transplant that assumption alone.
© MengTo, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
SKILL.md and 2 other files in agent-skills/3d/3d-sky-rays of MengTo/Skills.
- SKILL.md
- REFERENCES.md
- agents/openai.yaml
Open the folder on GitHubat commit 83a47fe
Compare with similar skills
3D Sky Rays next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| 3D Sky Rays this skillMengTo/Skills | 6.6k | — | ~1.2k | Automated safety check: Pass | MIT | |
| Image to Three.js Modelimg2threejs/img2threejs | 18k | 1 repos | ~8.2k | Automated safety check: Pass | Apache-2.0 | |
| Web CloneJane-xiaoer/claude-skill-web-clone | 1k | 1 repos | ~2.7k | Automated safety check: Pass | MIT | |
| Threejs Game Directormajidmanzarpour/threejs-game-skills | 2.4k | — | ~2.2k | Automated safety check: Pass | MIT | |
| Threejs Gameplay Systemsvalkor-ai/loom | 1.2k | 1 repos | ~1.4k | Automated safety check: Pass | Apache-2.0 | |
| Threejs World Generationcalesthio/OpenMontage | 65k | — | ~2k | Automated safety check: Pass | AGPL-3.0 |
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Related
Works with
Categories
Questions about 3D Sky Rays
What does 3D Sky Rays do?
Add sun shafts and crepuscular rays to a Three.js or equivalent 3D scene, using scene occlusion, a projected sun position, controlled foreground spill, and scalable post-processing. 3D Sky Rays is an agent skill from MengTo/Skills.js or equivalent 3D scene, using scene occlusion, a projected sun position, controlled foreground spill, and scalable post-processing.
When should I use 3D Sky Rays?
3D Sky Rays fits situations like: rays of light from the sky; sunlight through trees; golden-hour architectural scenes.
How do I install 3D Sky Rays in Claude Code?
Run `npx skills add MengTo/Skills --skill 3d-sky-rays -a claude-code`. Or copy the skill folder (agent-skills/3d/3d-sky-rays in MengTo/Skills) into .claude/skills/3d-sky-rays in your project. Claude Code loads it when a task matches its description.
How do I install 3D Sky Rays in Codex?
Run `npx skills add MengTo/Skills --skill 3d-sky-rays -a codex`. Or copy the skill folder (agent-skills/3d/3d-sky-rays in MengTo/Skills) into .agents/skills/3d-sky-rays in your project. Codex loads it when a task matches its description.
Can I use 3D Sky Rays in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add MengTo/Skills --skill 3d-sky-rays -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/3d-sky-rays, .gemini/skills/3d-sky-rays, .github/skills/3d-sky-rays and .opencode/skills/3d-sky-rays in your project.
What does 3D Sky Rays need to run?
Going by SKILL.md and its folder, 3D Sky Rays needs the command-line tools its instructions call (uv).
Does 3D Sky Rays access the network?
SKILL.md contains no URLs. Its commands use uv, which can reach the network depending on how they are called. This is read from the text; nothing was executed.
Is 3D Sky Rays safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does 3D Sky Rays use?
3D Sky Rays is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does 3D Sky Rays use?
About 1.2k tokens (SKILL.md is roughly 4.9k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to 3D Sky Rays?
Skills that share tags, products or a category with 3D Sky Rays: Image to Three.js Model (img2threejs/img2threejs, 18k stars), Web Clone (Jane-xiaoer/claude-skill-web-clone, 1k stars), Threejs Game Director (majidmanzarpour/threejs-game-skills, 2.4k stars) and Threejs Gameplay Systems (valkor-ai/loom, 1.2k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains 3D Sky Rays?
MengTo (a GitHub user) maintains it in MengTo/Skills, which has 6,647 GitHub stars. The repository holds 39 skills in this directory. The repository was last updated on October 6, 2026.
Source: MengTo/Skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.