threejs-impl-shadows

threejs-impl-shadows is a skill for Claude Code, Codex from Impertio-Studio/Three.js-Claude-Skill-Package. It costs 118 tokens per session (2,674 once invoked), scanned A, original, MIT.

A guide for adding shadows to Three.js scenes and fixing artifacts such as unwanted marks, detached shadows, or low-detail shadow edges.

In plain words
What is it for?
Use it to enable shadow maps, configure shadow quality, tune light settings, and set which meshes cast or receive shadows.
Why use it?
It explains the separate renderer, light, and mesh settings required for shadows to appear correctly.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions Claude Code.

Good fit Use it to enable shadow maps, configure shadow quality, tune light settings, and set which meshes cast or receive shadows.

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Install with agentmods
npx agentmods add skills/impertio-studio/three.js-claude-skill-package/threejs-impl-shadows
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.

Any agent
npx skills add Impertio-Studio/Three.js-Claude-Skill-Package --skill threejs-impl-shadows
Clone the repo
git clone --depth 1 https://github.com/Impertio-Studio/Three.js-Claude-Skill-Package

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for threejs-impl-shadows

README.md
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Your own site
<a href="https://agentmods.dev/skills/impertio-studio/three.js-claude-skill-package/threejs-impl-shadows"><img src="https://agentmods.dev/badge/skills/impertio-studio/three.js-claude-skill-package/threejs-impl-shadows.svg" alt="Measured on agentmods" height="20"></a>
Per session 118 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,674 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00118 $0.02674
Opus 5 $0.00059 $0.01337
Sonnet 5 $0.00024 $0.00535
Haiku 4.5 $0.00012 $0.00267

Measured 7d ago against content hash a97f772a19aa, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

threejs-impl-shadows 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 7d 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.

skills/source/threejs-impl/threejs-impl-shadows/SKILL.md · 318 lines

How it starts

The opening of the file, as written. The whole thing — 318 lines — stays where its author put it; the contents beside it link to each section on GitHub.

threejs-impl-shadows

Quick Reference

Three-Step Shadow Opt-In

Shadows in Three.js require THREE explicit opt-in steps. Missing ANY step results in no shadows.

import * as THREE from 'three';

// Step 1: Enable shadow maps on the renderer
renderer.shadowMap.enabled = true;
renderer.shadowMap.type = THREE.PCFSoftShadowMap;

// Step 2: Enable shadow casting on the light
light.castShadow = true;

// Step 3: Enable per-mesh shadow behavior
mesh.castShadow = true;       // this mesh casts shadows
ground.receiveShadow = true;  // this mesh receives shadows

Shadow Map Types

Type Constant Quality Cost Supports .radius
Basic THREE.BasicShadowMap Hard edges, aliased Lowest No
PCF THREE.PCFShadowMap Slightly softened Moderate No
PCF Soft THREE.PCFSoftShadowMap Soft penumbra Higher No (ignores it)
VSM THREE.VSMShadowMap Gaussian blur Moderate Yes
  • Default in r160+: THREE.PCFShadowMap
  • PCFSoftShadowMap: best general-purpose choice; IGNORES the shadow.radius property
  • VSMShadowMap: supports shadow.radius and shadow.blurSamples but can exhibit light bleeding on thin geometry

Critical Warnings

NEVER forget any of the three opt-in steps -- missing even one produces zero shadows with no error message.

NEVER leave the DirectionalLight shadow camera frustum at default size -- it is almost ALWAYS wrong for your scene. ALWAYS configure it manually.

NEVER use more than 1-2 shadow-casting PointLights -- each PointLight shadow renders 6 cubemap faces per frame.

ALWAYS set shadow.mapSize to power-of-two values (512, 1024, 2048, 4096).

ALWAYS add light.target to the scene when repositioning a DirectionalLight or SpotLight target.


Shadow Map Types -- Detailed Comparison

BasicShadowMap

No filtering applied. Produces hard, aliased shadow edges. Use ONLY for debugging or stylized rendering where hard shadows are intentional.

Read the full file on GitHub · 318 lines

Files

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.

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. 7d ago First seen · 318 lines · 118 tokens per session scan A a97f772a19aa

Subscribe to this mod's changes

threejs-impl-shadows is a skill published in the GitHub repository Impertio-Studio/Three.js-Claude-Skill-Package (11 stars, last pushed 2mo ago), licensed MIT. It adds 118 tokens to every session and 2,674 once invoked, about $0.0006 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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