Unity 计算子节点位置

using UnityEngine;

public class Test : MonoBehaviour {

    public Transform m_Father;
    public Transform m_Child;

    Vector3 m_OffestPos;
    Quaternion m_ChildOriRotation;
    Quaternion m_FatherOriRotation;

    void Start () {
        m_OffestPos = m_Child.position - m_Father.position;
        m_ChildOriRotation = m_Child.rotation;
        m_FatherOriRotation = m_Father.rotation;
    }
    
    void Update () {
        var deltaRotation = m_Father.rotation * Quaternion.Inverse(m_FatherOriRotation);
        m_Child.position = m_Father.position + deltaRotation * m_OffestPos;
        m_Child.rotation = deltaRotation * m_ChildOriRotation;
    }
}