Three.js seems to allow you to load geometry from OBJ files (Blender, 3DsMax, etc.), but is there any support for exporting a Three.js scene to an OBJ file (or any other formats)?
Having carefully examined the GitHub repository, I found the exporter of OBJ (not supplied with the .js tag):
var exporter = new THREE.OBJExporter(); exporter.parse(mesh);