HoldCube.cs

using UnityEngine;
using System.Collections;
using RootMotion.FinalIK;

public class HoldCube : MonoBehaviour {

	public FullBodyBipedIK ik;
	public Transform leftHandTarget, rightHandTarget;
	
	// Update is called once per frame
	void LateUpdate () {
		//左手
		ik.solver.leftHandEffector.position = leftHandTarget.position;
		ik.solver.leftHandEffector.rotation = leftHandTarget.rotation;
		ik.solver.leftHandEffector.positionWeight = 1f;
		ik.solver.leftHandEffector.rotationWeight = 1f;

		//右手
		ik.solver.rightHandEffector.position = rightHandTarget.position;
		ik.solver.rightHandEffector.rotation = rightHandTarget.rotation;
		ik.solver.rightHandEffector.positionWeight = 1f;
		ik.solver.rightHandEffector.rotationWeight = 1f;
	}
}