have problem when use scene.registerBeforeRender in importmesh

[lousha]

           BABYLON.SceneLoader.ImportMesh("", "model/", "weixin.babylon", scene, function (newMeshes, particleSystems, skeletons) {


                var alpha = 0;
                scene.registerBeforeRender( function () {

                    for (i = 0; i < 60; i++) {
                        newMeshes[i].position = new BABYLON.Vector3(newMeshes[i].position.x + 10 * 
                        Math.sin(alpha),
                            newMeshes[i].position.y + 0,
                            newMeshes[i].position.z + 10 * Math.cos(alpha));
                    }
                    alpha += 0.01;

                });
            });

here is  my code  why  it show "Cannot read property 'position' of undefined"

[Wingnut]

Hi Lousha, welcome to the forum.  Could you please insert this line after the importMesh...

console.log(newMeshes.length);

Then RUN and check JS console.

We want to make sure that there are, at least... 60 mesh inside the newMeshes array.  (thx for check)

Another possible test... console.log(newMeshes[59])... this should NOT report undefined, of course.

Talk again soon.