How to get the mouse clicking position on an obj file loaded from OBJLoader?

I loaded the model using OBJLoader, here is the code for loading the obj file: ``` var loader = new THREE.OBJLoader(); loader.load('obj/teeth/teeth4_5.obj', function(object) { model = object; scene.add( model ); objects.push( model ); }); ``` And I'm trying to use raycaster to find the intersection. I implemented my code from the canvas_interactive_cubes example (http://mrdoob.github.io/three.js/examples/canvas_interactive_cubes.html) in three.js. Here is the code to find the intersection: ``` function onDocumentMouseDown( event ){ event.preventDefault(); var mouseX = (event.clientX / window.innerWidth)*2-1; var mouseY = -(event.clientY /window.innerHeight)*2+1; var vector = new THREE.Vector3( mouseX, mouseY, 0.5 ); projector.unprojectVector( vector, camera ); var raycaster = new THREE.Raycaster( camera.position, vector.sub( camera.position ).normalize() ); var intersects = raycaster.intersectObjects( scene.children ); console.log( intersects[0].point); } ``` Unfortunately I'm not able to get the x,y,z coordinates of the intersection, no matter where I clicked, it always showed "TypeError: intersects[0] is undefined". I'm getting stuck here for several days. Can someone tell me a way to get the intersection on a loaded obj file? I appreciate your help.