How do I make a planet get sucked into a blackhole ?

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1

I am trying to get a gameobject (planet) to orbit another gameobject (blackhole) in gradually smaller orbits until the planet collides with the blackhole.

This is my current code:

var BlackHoleCenter : Transform;

function FixedUpdate(){

    transform.RotateAround (BlackHoleCenter.transform.position, Vector3(1, 0, 0), 200 * Time.deltaTime);
    transform.LookAt(BlackHoleCenter);
    rigidbody.AddForce(transform.forward*50);
}

If I comment out the transform.RotateAround line, the planet approaches the blackhole gradually as desired, but if I allow the transform.RotateAround line to run, the planet orbits, but never approaches the blackhole.

Why is this?

2 Answers

2
2

You mixed direct movement(RotateAround) with physic driven movement(AddForce). I recommend to use just direct movement, because you specify all values and the movement isn't really physic based.

var BlackHoleCenter : Transform;

function FixedUpdate(){

    transform.RotateAround (BlackHoleCenter.transform.position, Vector3(1, 0, 0), 200 * Time.deltaTime);
    transform.LookAt(BlackHoleCenter);
    transform.Translate(Vector3.forward*50*Time.deltaTime);
}

You may need to adjust your "50" because it's no longer a force, it's a speed now.

Wow, thank you.

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3

You could also use physics for it by using:

var BlackHoleCenter : Transform;

function FixedUpdate()
{
    transform.LookAt(BlackHoleCenter);
    rigidbody.AddForce(transform.forward*50);
    rigidbody.AddForce(transform.right*50);

}

This will make the rigidbody be purely physics based meaning you can alter its trajectory during gameplay using other obects/forces.