I set transform.forward perfect in horizontal move, but when i use it in vertical move, see my gif, transform.forward = newForward will cause transform.position change, how to make character forward but don't change transform.position

here is my full script:

public class TestVerticalMoveForward : MonoBehaviour

{

    private GameObject from;



    private GameObject to;

    private GameObject target;



    // Use this for initialization

    void Start()

    {

        from = GameObject.Find("From");

        to = GameObject.Find("To");

        target = from;

    }



    private float speed = 10;



    // Update is called once per frame

    void Update()

    {

        var offset = target.transform.position - transform.position;

        var forward = offset.normalized;

        var offset2 = speed * Time.deltaTime * forward;

        if (offset.magnitude <= offset2.magnitude)

        {

            transform.position = target.transform.position;

            if (target == to)

            {

                target = from;

            }

            else

            {

                target = to;

            }

        }

        else

        {

            transform.position += offset2;

        }



        if (offset != Vector3.zero)

        {

            transform.forward = offset;

        }

    }

}

I find the solution and reason,

solution:

here is fixed result

I use Quaternion.LookRotation instead of transform.forward=

#if UNITY_EDITOR

using System.Collections;

using System.Collections.Generic;

using Script.Ro.Ext;

using UnityEngine;



public class TestVerticalMoveForward : MonoBehaviourExt

{

    private GameObject from;



    private GameObject to;



    private GameObject target;

//    private GameObject center;



    // Use this for initialization

    void Start()

    {

        from = GameObject.Find("From");

        to = GameObject.Find("To");

//        center = GameObject.Find("Character/Center");

        target = from;

    }



    private float speed = 10;



    // Update is called once per frame

    void Update()

    {

        Watch("center.transform.position", transform.position);

        var offset = target.transform.position - transform.position;



        var forward = offset.normalized;

        var offset2 = speed * Time.deltaTime * forward;

        if (offset.magnitude <= offset2.magnitude)

        {

            transform.position += offset;

            if (target == to)

            {

                target = from;

            }

            else

            {

                target = to;

            }

        }

        else

        {

            transform.position += offset2;

        }



        if (offset != Vector3.zero)

        {

           var upAxis =  transform.rotation * Vector3.up;

            transform.rotation =

                Quaternion.LookRotation(target.transform.position - transform.position, upAxis);

        }

    }

}

#endif

reason

unity has

Quaternion LookRotation(Vector3 forward, Vector3 upwards = Vector3.up);

I guess transform.forward = invoke internal LookRotation code and always set upwards = Vector3.up(y axis), in horizontal move, it work perfect, but in vertical move, it perform unexpectly

so imagine object has center-up-axis, for ex, to humanoid object, the up axis, is body center to head center axis, to make sure vertical move perform like horizontal move, LookRotation's upwards should always be center-up-axis, see my above code, this center-up-axis should be:

       var upAxis =  transform.rotation * Vector3.up ;