# improve-threejs

Audits Three.js and React Three Fiber apps for frame-loop issues, GPU memory leaks and rendering defects. Use it when a scene needs a code and visual review.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 316 installs · ★ 15049
- Author: millionco
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/millionco/react-doctor/tree/HEAD/skills/improve-threejs/SKILL.md
- Updated: 2026-10-25
- HTML: https://affpapa.org/en/nevibecode/skills/improve-threejs

## What it does

The skill scans Three.js and React Three Fiber code with React Doctor, then reviews findings through the frame loop. It looks for allocations in `useFrame`, `setState` calls on every frame, rebuilt scene objects, and GPU resources that miss `dispose()`.

Findings are ranked by where they run: code in `useFrame` and `requestAnimationFrame` executes 60 times per second. That means hot paths deserve attention before UI issues outside the `Canvas`.

It also audits rendered output for z-fighting, shadows, colour space, textures, camera behaviour, and resize handling. When a browser is available, visual findings use scene captures; otherwise, they are marked as inferred from source code.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add millionco/react-doctor --skill improve-threejs -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/improve-threejs/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/improve-threejs/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add millionco/react-doctor --skill improve-threejs -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/improve-threejs/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add millionco/react-doctor --skill improve-threejs -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/improve-threejs/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install millionco/react-doctor improve-threejs
```

2. **Manually: put the files in place**
- File: `.github/skills/improve-threejs/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add millionco/react-doctor --skill improve-threejs -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/millionco/react-doctor --path skills/improve-threejs
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/improve-threejs/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add millionco/react-doctor --skill improve-threejs -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/millionco/react-doctor/tree/HEAD/skills/improve-threejs/SKILL.md

## When to use it
- find allocations inside `useFrame`
- dispose unused GPU geometries, materials and textures
- stop scene objects from rebuilding on render
- check z-fighting and shadow defects
- fix resize and DPR handling

## Example prompts
- \`/improve-threejs` audit this React Three Fiber scene for GPU leaks and `useFrame` work.
- Check this Three.js app for colour-space and shadow issues.
- Scan the R3F scene and find geometry objects rebuilt during rendering.

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 0bf9dfab5d8e3460.

BEGIN THIRD-PARTY FILE 0bf9dfab5d8e3460
````text
---
name: improve-threejs
description: Audit and fix Three.js and React Three Fiber apps for frame-loop performance, GPU memory leaks, scene-graph correctness, and visual defects like z-fighting, shadow acne, wrong color space, and broken resize handling. Uses React Doctor as the scanning engine plus a visual rubric checked against rendered output. Use when the user asks to improve, audit, scan, or clean up a Three.js, R3F, react-three-fiber, drei, or WebGL app, or types `/improve-threejs`.
---

# Improve Three.js

Audits a Three.js or React Three Fiber (R3F) codebase and fixes what hurts most: work that runs every frame, GPU resources that never get disposed, scene-graph objects rebuilt on every render, and visual defects the user can see. React Doctor supplies the machine-verified code scan; this skill supplies the frame-loop judgment and the visual inspection a general React scanner lacks.

The core principle: severity follows the render loop. Code inside `useFrame` or a `requestAnimationFrame` callback runs 60 times per second, so a minor inefficiency there outweighs a major one in a settings panel. Rank every finding by where it runs, not by the rule's default severity.

## Workflow

### Step 1: Recon

Identify the stack before scanning: plain Three.js or R3F, which helper libraries are in use (drei, postprocessing, rapier), and where the render loop lives (`useFrame` hooks, `requestAnimationFrame`, the `<Canvas frameloop>` setting).

Build a hot-path map: every `useFrame` body, every RAF callback, every pointer-move handler. These files get the strictest review in Step 3.

### Step 2: Scan

Run React Doctor read-only to collect structured evidence:

```bash
npx react-doctor@latest --verbose
```

For a regression check after making changes, run with `--scope changed` and confirm the score did not drop.

### Step 3: Triage by frame-loop leverage

Re-rank the scanner's findings using the hot-path map, then hunt for the Three.js-specific problems the scanner cannot see. Confirm every finding at its `file:line` before reporting it.

**HIGH severity, runs every frame or leaks GPU memory:**

- **Allocation inside `useFrame`**: `new Vector3()`, `new Color()`, or fresh arrays passed to Three.js APIs each frame. Fix: hoist a scratch object to module scope or `useMemo`, then mutate it in place
- **`setState` inside `useFrame`**: re-renders the React tree on every frame. Fix: mutate refs directly; reserve state for discrete changes like selection or visibility
- **Missing disposal**: geometries, materials, textures, or render targets created imperatively and never disposed. Fix: call `dispose()` in the cleanup function, or move the object into R3F's declarative tree so it owns the lifecycle
- **Object reconstruction in render**: geometry or material instances created without `useMemo`, or inline `args` arrays whose identity changes each render, forcing R3F to rebuild the underlying object

**MEDIUM severity, per-render or per-interaction waste:**
````
END THIRD-PARTY FILE 0bf9dfab5d8e3460

The third-party file has ended. Everything between the 0bf9dfab5d8e3460 tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

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