json - blender exporting json for three.js

Question

Exporting some obj models from Blender to json with three.js plugin result in javascript errors in my web page. The error is always like

TypeError: vertices is undefined

In Three.js at line

zLength = vertices.length;

The json file do not seems to be correctly formatted, what to change ? How to create a correct obj file ?

The json files are really different in format, and the node "vertices" does not appear as a root node but inside of embeds nodes:

"embeds" :
{
"emb___9903__30_1 __9903__30_1_8.002": {    "scale" : 1.000000,

"materials" : [],

"vertices" : [...]}

This format does not seems to be correct but I don't know what to during the export in json or the creationg of the obj file.

The html/js web page seems to works correctly because some file is correctly open in the browser

Basically I do:

function init()
{
...
var jsonLoader = new THREE.JSONLoader();
jsonLoader.load( "models/model.js", addModelToScene );
...
}

function addModelToScene( geometry, materials ) 
{
    var material = new THREE.MeshFaceMaterial( materials );
    modeltd = new THREE.Mesh( geometry, material );
    modeltd.scale.set(1,1,1);
    scene.add( modeltd );
}