I have uploaded a demo here so you see what the problem is. The car
falls through the lower race track piece.
Here is the updated code:
private function onResourceRetrieved(event : ResourceEvent) : void
{
if(event.uri=="assets/scene2.obj"){
_containerCity =
ObjectContainer3D(event.resource);
view.scene.addChild(_containerCity);
gameMaterial.shadowMethod = new
SoftShadowMapMethod(light);
gameMaterial.ambientColor = 0x2A2A2A;
gameMaterial.gloss = 100;
gameMaterial.specular = .6;
gameMaterial.lights = [light];
var
mesh:Mesh=Mesh(_containerCity.getChildAt(0));
mesh.castsShadows = true;
mesh.geometry.scale(100);
mesh.material = gameMaterial;
var mclone:ObjectContainer3D =
ObjectContainer3D(_containerCity.getChildAt(0).clone());
mclone.z = -2100;
mclone.y = -40;
view.scene.addChild(mclone);
//create the triangle mesh
physics.createMesh(mesh, new Vector3D(), new
Matrix3D(), 10, 10);
physics.createMesh(Mesh(mclone), new
Vector3D(), new Matrix3D(),
10, 10);