Transform.forward changes by double the amount of rotation?

Unity Engine
,
1

I have an object that with the following code:

[SerializeField] private float speed = 10f;
public bool go;

void Update()
{
    if (rb.velocity.magnitude < .2f && go)
    {
        rb.AddRelativeForce(speed * Time.deltaTime * transform.forward);
    }

    if (!go)
    {
        rb.velocity = Vector3.zero;
    }
   
}

With no other input, transform.forward move the object positively in the z-axis, but if I rotate the object in the inspector to Y:90, the movement does a 180 and starts going negatively in the z-axis. If I do Y:45 it moves positive X. Same thing with X-axis rotation, X:90 goes backwards, X:45 goes negative Y.

Am I missing something? Why does transform.forward change by 2x the rotation I give the object?

2

I think you’re mixing coordinate systems.

Transform.forward is in World Space, and AddRelativeForce is local space.

So you either want to use AddForce with transform.forward, or AddRelativeForce with Vector3.forward

3

Just pointing that out made me realize why that was wrong. Thanks. Using AddForce with transform.forward has fixed it.