Animatorで重力

gistfile1.cs

using UnityEngine;
using System.Collections;

[RequireComponent(typeof(Animator))]
[RequireComponent(typeof(CharacterController))]
public class RobotController : MonoBehaviour
{
  private Animator animator;
	private CharacterController characterController;

	void Start ()
	{
		animator = GetComponent<Animator> ();
		characterController = GetComponent<CharacterController> ();
	}
	
	void Update ()
	{
		animator.SetFloat ("run", Input.GetAxis ("Vertical"));
		animator.SetFloat ("dir", Input.GetAxis ("Horizontal"));
	}

	private Vector3 gravityVelocity = Vector3.zero;

	void OnAnimatorMove ()
	{
		Vector3 pos = animator.deltaPosition;
		transform.rotation = animator.rootRotation;
		
		if (characterController.isGrounded == false) {
			pos += gravityVelocity += Vector3.down * animator.gravityWeight * Time.deltaTime;
		} else {
			gravityVelocity = Vector3.zero;
		}
		
		characterController.Move (pos);
	}
}