@layergen/mesh-repair

@layergen/mesh-repair

Pure-Node mesh-repair primitives. Single source of truth for layergen's mesh-fixing logic (BVH-checked 3D ear-clipping, footprint-aware base plates, tri-tri intersection detection, etc.) — imported directly by both:

• src/stlOpsWorker.js — the browser repair tool's web worker
• @layergen/mcp — the Node-side MCP server's repair tools

Anyone fixing a bug or adding a feature here automatically improves both surfaces. No copy-paste, no auto-generation, no drift.

What it does

Operates on raw Float32Array positions and Uint32Array indices (or non-indexed buffers) — no DOM, no three.js dependency in the core, no worker globals. Just CPU-bound geometry math that runs identically on any modern Node or browser environment.

three.js IS used by geometry.js for STL load/save and addBasePlate (BoxGeometry primitive); those are isolated from raw.js.

Layout

packages/mesh-repair/
├── package.json
├── src/
│   ├── index.js     # public API (re-exports)
│   ├── raw.js       # the *Raw primitives (typed-array in/out)
│   ├── score.js     # analyzeMeshRaw — print-readiness scoring
│   └── geometry.js  # STL I/O + addBasePlate (uses three.js)
└── test/
    ├── smoke.test.mjs       # raw functions on a synthetic broken cube
    └── geometry.test.mjs    # STL round-trip + base-plate clamping

Public API

import {
  // Analysis
  analyzeMeshRaw,            // { score, verdict, issues, fixes, stats }
  // High-level pipeline
  aggressiveRepairRaw,       // merge → remove-shells → fill-holes → remove-non-manifold
  // Individual ops
  mergeVerticesRaw,
  removeFloatingShellsRaw,
  fillHolesRaw,
  removeNonManifoldRaw,
  decimateRaw,
  autoOrientRaw,
  countBoundariesQuick,
  makeNormalsConsistent,
  // STL I/O + base plate
  loadStlBytes,
  exportStlBytes,
  computeBoundingBox,
  addBasePlate,
} from "@layergen/mesh-repair";

All raw operations follow the same shape:

const { positions, indices, meta } = mergeVerticesRaw(
  positionsIn,           // Float32Array, flat xyzxyz...
  indicesIn,             // Uint32Array (or null for non-indexed)
  precision,             // function-specific args
  // optional progress callback (defaults to no-op)
  // (pct, msg) => console.log(`${pct}%`, msg),
);

indices may be null in the output — that means the function de-indexed the mesh (one tri = 9 floats in positions). Check meta for op-specific diagnostics like meta.removedTriangles, meta.keptShells, etc.

Editing

Just edit src/raw.js, src/score.js, or src/geometry.js directly. Both the web worker and the MCP server pick up changes on next bundle / next install. No more extract-raw.mjs — the dedup landing (2026-05-01) made the worker import from this package, eliminating the copy-paste flow.

Testing

cd packages/mesh-repair
npm install     # earcut + three (only deps)
npm test

11 tests cover STL round-trip, base-plate sub-mm clamping, and every *Raw function on a synthetic cube-with-hole.