add physics on blender model, three.js Physijs

How can i add physics on a blender model ? I tried ConvexMesh, ConcaveMesh but no luck.

var mesh = {... blender exporter ...}

var loader = new THREE.JSONLoader();
var mesh_obj = loader.parse(mesh,'./');
var mesh_materials = mesh_obj.materials;
var mesh_geometry = mesh_obj.geometry;

var _materials=[];
for ( var i = 0, i<mesh_materials.length;i ++ ) {
 var materialv = Physijs.createMaterial(mesh_materials[i],0.8,0.1);
 _materials.push(materialv)
}

mesh = new Physijs.ConcaveMesh(mesh_geometry, new THREE.MeshFaceMaterial(_materials),0 );
scene.add(mesh)