Proper way to move Rigidbody GameObject

Question

I just started learning Unity. I tried to make a simple box move by using this script. The premise is, whenever someone presses 'w' the box moves forward.

public class PlayerMover : MonoBehaviour {

public float speed;
private Rigidbody rb;


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

public void Update () {
    bool w = Input.GetButton("w");

    if (w) {
        Vector3 move = new Vector3(0, 0, 1) * speed;
        rb.MovePosition(move);
        Debug.Log("Moved using w key");

    }

}
}

Whenever I use this, the box doesn't move forward on a 'w' keypress. What is wrong with my code? I thought it might be the way I have my Vector 3 move set up so I tried replacing the z-axis with speed, but that didn't work. Could someone tell me where I am messing up?

Answer 1

You move Rigidbody with Rigidbody.MovePosition and rotate it with Rigidbody.MoveRotation if you want it to properly collide with Objects around it. Rigidbody should not be moved by their position, rotation or the Translate variables/function.

The "w" is not predefined like SherinBinu mentioned but that's not the only problem. If you define it and use KeyCode.W it still won't work. The object will move once and stop.

Change

Vector3 move = new Vector3(0, 0, 1) * speed;
rb.MovePosition(move);

to

tempVect = tempVect.normalized * speed * Time.deltaTime;
rb.MovePosition(transform.position + tempVect);

This should do it:

public float speed;
private Rigidbody rb;


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

public void Update()
{
    bool w = Input.GetKey(KeyCode.W);

    if (w)
    {
        Vector3 tempVect = new Vector3(0, 0, 1);
        tempVect = tempVect.normalized * speed * Time.deltaTime;
        rb.MovePosition(transform.position + tempVect);
    }
}

---

Finally, I think you want to move your object with wasd key. If that's the case then use Input.GetAxisRaw or Input.GetAxis .

public void Update()
{
    float h = Input.GetAxisRaw("Horizontal");
    float v = Input.GetAxisRaw("Vertical");

    Vector3 tempVect = new Vector3(h, 0, v);
    tempVect = tempVect.normalized * speed * Time.deltaTime;
    rb.MovePosition(transform.position + tempVect);
}

Answer 2

"w" is not predefined unless you explicitly define it. Use KeyCode.W

Answer 3

Try this:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class PlayerMover : MonoBehaviour {

    public float speed;
    private Rigidbody rb;


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

    void Update () {
        bool w = Input.GetKey(KeyCode.W);

        if (w) {
            Vector3 move = new Vector3(0, 0, 1) * speed *Time.deltaTime;
            rb.MovePosition(move);
            Debug.Log("Moved using w key");

        }

    }
}

Use Input.GetKey(KeyCode.W) for getting input.
EDIT NOTE : To move the object relative to its initial position use rb.MovePosition(transform.position+move) rather than rb.MovePosition(move)

Answer 4

Instead of making w a bool, you can use axis, also, in unity editor you should make it so the rigidbody movement is frozen

here is some code

void update()
{
    rb.AddForce(Input.GetAxis("Horizontal"));
}

Answer 5

bool w = Input.GetKeyDown(KeyCode.W);