A simple, fast glTF model viewer.

See it in action at: https://www.virtualgis.io/gltfviewer/
It uses Cesium for rendering. Files are read via HTML5 File API, so it's fast. No files are ever uploaded to a server.
git clone https://github.com/virtualgis/gltfviewer
cd gltfviewer
npm install
python -m http.server
This assumes Python 3.x is installed to launch the local web server.