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.
npx skills add Impertio-Studio/Three.js-Claude-Skill-Package --skill threejs-core-mathgit clone --depth 1 https://github.com/Impertio-Studio/Three.js-Claude-Skill-PackageWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/impertio-studio/three.js-claude-skill-package/threejs-core-math)<a href="https://agentmods.dev/skills/impertio-studio/three.js-claude-skill-package/threejs-core-math"><img src="https://agentmods.dev/badge/skills/impertio-studio/three.js-claude-skill-package/threejs-core-math/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/impertio-studio/three.js-claude-skill-package/threejs-core-math"><img src="https://agentmods.dev/badge/skills/impertio-studio/three.js-claude-skill-package/threejs-core-math.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00130 | $0.02958 |
| Opus 5.5 | $0.00052 | $0.01183 |
| Sonnet 5.5 | $0.00026 | $0.00592 |
| Haiku 4.5 | $0.00013 | $0.00296 |
Grade A, and why
threejs-core-math 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 1mo 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.
How it starts
The opening of the file, as written. The whole thing — 259 lines — stays where its author put it; the contents beside it link to each section on GitHub.
threejs-core-math
Quick Reference
Coordinate System
Three.js uses a right-handed coordinate system with Y-up:
| Axis | Direction | Notes |
|---|---|---|
| X | Right | Positive toward screen right |
| Y | Up | Positive toward ceiling |
| Z | Toward viewer | Positive out of the screen |
Import conversion rules:
| Source | Convention | Conversion |
|---|---|---|
| Blender | Z-up | glTF exporter converts automatically |
| FBX | Z-up | FBXLoader converts automatically |
| OBJ | No standard | ALWAYS verify orientation after loading |
| IFC | Z-up | ALWAYS apply -90 degree X rotation or use a converting loader |
NEVER assume imported models match Three.js conventions -- ALWAYS verify orientation after loading.
Core Math Classes
| Class | Purpose | Identity/Default |
|---|---|---|
Vector3 |
Position, direction, scale | (0, 0, 0) |
Vector2 |
UV coordinates, 2D positions | (0, 0) |
Vector4 |
Homogeneous coordinates, shader data | (0, 0, 0, 0) |
Matrix4 |
4x4 transformation matrix | Identity matrix |
Quaternion |
Rotation without gimbal lock | (0, 0, 0, 1) |
Euler |
Human-readable rotation angles | (0, 0, 0, 'XYZ') |
Color |
RGB color (0-1 range) | (1, 1, 1) white |
Box3 |
Axis-aligned bounding box | Empty (+Inf min, -Inf max) |
Sphere |
Bounding sphere | Center origin, radius -1 |
Plane |
Infinite plane | Normal (1,0,0), constant 0 |
Ray |
Origin + direction | Origin (0,0,0), direction (0,0,-1) |
Frustum |
6-plane view frustum | -- |
Critical Warnings
NEVER modify a Vector3/Matrix4/Quaternion that is shared between objects -- most methods mutate in-place. ALWAYS use .clone() before modifying shared instances.
// WRONG: mutates the shared vector
const offset = new Vector3(1, 0, 0);
meshA.position.add(offset);
meshB.position.add(offset); // offset is still (1, 0, 0) BUT if you
// had stored meshA.position somewhere,
// it would be mutated
// CORRECT: clone before mutation
const pos = sharedPosition.clone().add(offset);
What ships with it
4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 1mo ago First seen · 259 lines · 130 tokens per session scan A bae9c0bcd1ab
threejs-core-math is a skill published in the GitHub repository Impertio-Studio/Three.js-Claude-Skill-Package (23 stars, last pushed 3mo ago), licensed MIT. It adds 130 tokens to every session and 2,958 once invoked, about $0.0005 per session on Opus 5.5. 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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