polycss

A library for displaying 3D polygon models as ordinary web-page elements transformed with CSS. It works with vanilla JavaScript, React, and Vue, and supports several model formats and interactive scene features.

In plain words
What is it for?
Creating, porting, debugging, or explaining PolyCSS scenes, including models, primitive shapes, lighting, shadows, controls, animation, and polygon interaction.
Why use it?
It lets developers build browser-based 3D scenes without relying on WebGL or a continuously redrawn canvas.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/layoutit/polycss/skill
Any agent
npx skills add layoutit/polycss --skill skill
Clone the repo
git clone --depth 1 https://github.com/layoutit/polycss

Made for: Claude Code, Codex.

Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,529 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00052 $0.02529
Opus 5 $0.00026 $0.01264
Sonnet 5 $0.00010 $0.00506
Haiku 4.5 $0.00005 $0.00253

Measured 2d ago against content hash cf01b4c40f96, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

polycss scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

packages/skills/skill/SKILL.md · 210 lines

How it starts

The opening of the file, as written. The whole thing — 210 lines — stays where its author put it; the contents beside it link to each section on GitHub.

PolyCSS — DOM 3D Rendering

PolyCSS renders 3D polygon meshes as real DOM elements transformed with CSS matrix3d(...). No WebGL, no canvas-per-frame. It supports OBJ/MTL, STL, glTF/GLB, VOX, generated primitives, colors, textures, dynamic lighting, shadows, controls, selection, animation, and per-polygon interaction.

Use native PolyCSS when authoring PolyCSS-first scenes. Use the Three.js parity API when porting Three.js code or generating code from Three-shaped examples.

Reference docs

Read the file that matches the task before writing non-trivial code.

File Read it when
docs/authoring-polygons.md Generating Polygon[] by hand. Winding, color format, coplanarity, the optimizer. Silent-failure rules.
docs/scenes-and-cameras.md Setting up a scene, camera props, scene options, custom elements, coordinates.
docs/shapes-and-primitives.md Boxes, spheres, planes, Platonic solids, raw polygon generators.
docs/loading-models.md loadMesh, <PolyMesh src>, OBJ/MTL/STL/glTF/GLB/VOX, parse options.
docs/lighting.md Directional/ambient/point lights, baked vs dynamic, rebaking.
docs/shadows.md castShadow, receiveShadow, parametric shadows, renderer differences.
docs/textures.md UV textures, the atlas pipeline, texture quality, presentation options.
docs/controls-and-interaction.md Orbit/map/first-person controls, selection, transform gizmos, click handlers.
docs/animation.md Skeletal clips from glTF/GLB, usePolyAnimation, stable DOM.
docs/performance.md Leaf counts, render strategies, atlas memory, voxel fast paths.
docs/three-parity.md Porting Three.js scenes through the */three subpaths.
docs/troubleshooting.md Something renders wrong. Symptom → cause table.
docs/api-index.md "Does this export exist?" Package-by-package export inventory.

Read the full file on GitHub · 210 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 210 lines · 52 tokens per session scan A cf01b4c40f96

Subscribe to this mod's changes

polycss is a skill published in the GitHub repository layoutit/polycss (747 stars, last pushed 7d ago), licensed MIT. It adds 52 tokens to every session and 2,529 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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