How to move a player along Waypoints with Rigidbody.MovePosition in Unity?

Question

I have a player with a Rigidbody, I want it to follow along the Waypoints. I have used MoveTowards but it seems also not to work however. I want to use MovePosition to add force while grinding. I commented a code that could maybe work but I got an error on that, check //ADDFORCE lines.

Here is my code:

---

public GameObject[] waypoints;

public float grindSpeed;
public float turnSpeed;

public int currentWaypoint;

private Animator anim;
private Rigidbody rb;

public bool isGrinding = false;

void Start()
{
    anim = GetComponent<Animator>();
    rb = GetComponent<Rigidbody>();
}


void FixedUpdate()
{
    MoveAlongWaypoints();

    if(isGrinding)
        anim.SetBool ("isOnGrinding", true);
    else if(!isGrinding)
        anim.SetBool("isOnGrinding", false);
}

void MoveAlongWaypoints()
{
    if(isGrinding)
    {
        //TRANSLATE
        transform.position = Vector3.MoveTowards(transform.position, waypoints[currentWaypoint].transform.position, grindSpeed * Time.deltaTime);
        //ADDFORCE
        /*
        Vector3 movePosition = transform.position;
        movePosition = Mathf.MoveTowards(transform.position, waypoints[currentWaypoint].transform.position * grindSpeed * Time.deltaTime);
        rb.MovePosition(movePosition);
        */
        //ROTATE
        var rotation = Quaternion.LookRotation(waypoints[currentWaypoint].transform.position - transform.position);
        transform.rotation = Quaternion.Slerp(transform.rotation, rotation, turnSpeed * Time.deltaTime);

        if(Mathf.Abs(transform.position.x - waypoints[currentWaypoint].transform.position.x) < 1
            && (Mathf.Abs (transform.position.y - waypoints[currentWaypoint].transform.position.y) < 1)
            && (Mathf.Abs (transform.position.z - waypoints[currentWaypoint].transform.position.z) < 1))
        {
            //rb.useGravity = false;
            currentWaypoint++;
        }
    }
}

void OnTriggerEnter(Collider other)
{
    if(other.gameObject.tag == "GrindWayPoint")
    {
        Debug.Log ("Waypoint!!");
        isGrinding = true;
    }
}

Answer 1

It looks like your code should work... bump. I do have a few tips however.

1) try to work in FixedUpdate when working with Rigidbodies.

2) Use movePosition to move Rigidbodies, rather than setting the position.

The above 2 tips will cause your game to jitter less. If you use fixedUpdate to move a rigidbody, it could move through the collider without being detected in the physicssteps.

3) anim.SetBool ("isOnGrinding", isGrinding); is 3 lines of code less than the ones you already have in your fixedUpdate.

4) Vector3.distance() is also shorter than calculating the offset between all 3 axis of a vector3 seperately.

5) When using moveTowards, don't multiply your targetPosition by a float, this would give you an entirely different position. if you want to move it gradually, use Vector3.Lerp, or calculate the offset first.

Try to provide a bit more information too, it seems like it should work, but i don't really know anything about your setup. Do your waypoints have colliders on them? Or does the gameObject with the waypoints have a collider?

Answer 2

Your Vector3.MoveTowards and Rb.MoveTowards will works same. However you can use Vector3.Distance() instead of

if(Mathf.Abs(transform.position.x - waypoints[currentWaypoint].transform.position.x) < 1
        && (Mathf.Abs (transform.position.y - waypoints[currentWaypoint].transform.position.y) < 1)
        && (Mathf.Abs (transform.position.z - waypoints[currentWaypoint].transform.position.z) < 1))
    {
        //rb.useGravity = false;
        currentWaypoint++;
    }

You can use it like

Vector3.Distance(transform.position,waypoints[currentwaypoint].transfrom.positon)

It Will return float you can make a condition out of it. Also You are not considering trasnform.forward in your movement. Your player may not move using forward. You should check out this link.

https://docs.unity3d.com/ScriptReference/Rigidbody.MovePosition.html