How to create dynamic animator controller (state machine, transtion etc) with .fbx files by using c# script

I want to create dynamic animator controller by using .fbx file. Let us suppose that I have lots of .fbx files which contains animations and more. Now, at runtime I want that some of the .fbx file must be used (Let say two i.e. Arm1.fbx and Arm2.fbx) to create a dynamjc controller, after that this controller will apply on Avatar. How to assign .fbx file to animator controller using c# script?

// code for that Animator animator; void Start () {

 // Creates the controller
     var controller = UnityEditor.Animations.AnimatorController.CreateAnimatorControllerAtPath ("Assets/DynamicController/MyController.controller");

     Object ObjLoadController = AssetDatabase.LoadAssetAtPath("Assets/DynamicController/MyController.controller", (typeof(Object)));

     // Loading fbx files from a folder
      Object ObjLoadFbx = AssetDatabase.LoadAssetAtPath("Assets/fbxFromServer/Arms1.fbx", (typeof(Object)));

// Add parameters controller.AddParameter("TransitionNow",AnimatorControllerParameterType.Trigger);

// Add StateMachines var rootStateMachine = controller.layers[0].stateMachine; var stateMachineA = rootStateMachine.AddState("Arm1"); var stateMachineB = rootStateMachine.AddState("Arm2");