Rigidbody.addForce and Rigidbody.addRelativeForce won't work

Questions & Answers
1

I want to have a very basic game in which a sphere rolls around with the camera following it. I have it set up so when W is pressed it uses rb.addforce (rb being my rigidbody). When D is pressed it rotates the sphere using the Space.World. If I use rb.addForce it always pushed the sphere forward on the world axis regardless of if I rotate the sphere. If I use rb.addRelativeForce it will push the sphere in the direction the sphere is facing but because the sphere rolls forward my script ends up pushing the sphere down. Is there a way to use some axes of the local space and some of the world space for rotation?

Here is my Code:

    public float speed;

	private Rigidbody rb;

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

	void FixedUpdate ()
	{
		float moveVertical = Input.GetAxis ("Vertical");

		Vector3 movement = new Vector3 (0.0f, 0.0f, moveVertical);

		rb.AddRelativeForce (movement * speed);
		if (Input.GetKey ("a")) {
			transform.Rotate (0, -5, 0);
		}
		if (Input.GetKey ("d")) {
			transform.Rotate (0, 5, 0);
		}
	}
2

You can make an empty object and set it up to follow the sphere around like a camera, and then use that object a a reference for the rigidbody forces. This way the ball will still act under Unity physics because you won’t have to cut in to anything that’s happening to the ball already.