model-viewer

Lightweight browser-based STL and STEP viewer built on Three.js. Drop it anywhere — GitHub Pages, a VPS, whatever and point it at a model file via URL param.

Example: Setup

Usage

viewer.html?file=https://raw.githubusercontent.com/you/repo/main/part.stl
viewer.html?file=https://github.com/you/repo/blob/main/part.step

GitHub blob URLs are rewritten to raw automatically.

Flags

?file=…&flags=edit,upload

Flag	What it does
edit	Scale input, Auto Orient, Confirm
upload	Local file picker (.stl / .step / .stp)

Formats

• STL — binary and ASCII
• STEP — via OpenCASCADE WASM (occt-import-js), loads on demand

postMessage API

Send a model from a parent frame:

iframe.contentWindow.postMessage({
  type: "load_model",
  buffer: arrayBuffer,
  ext: "step"
}, "*")

Confirmation comes back as:

{ type: "model_confirmed", data: { rotation: [x, y, z], scale: 1 } }

Self-hosting

Single HTML file, no build step. Just serve it.