Gravity within range

Questions & Answers
1

This script gives an object gravity. but i want the gravity to only affect objects within a certain distance rather than from anywhere. How can i do this.

const float G = 667.4f;

public static List<Attractor> Attractors;

public Rigidbody rb;

private void FixedUpdate()
{
    foreach (Attractor attractor in Attractors)
    {
        if (attractor != this)
        Attract(attractor);
    }
}

void OnEnable ()
{
    if (Attractors == null)
        Attractors = new List<Attractor>();

    Attractors.Add(this);
}

private void OnDisable()
{
    Attractors.Remove(this);
}

void Attract (Attractor objToAttract)
{
    Rigidbody rbToAttract = objToAttract.rb;

    Vector3 direction = rb.position - rbToAttract.position;
    float distance = direction.magnitude;

    float forceMagnitude = G * (rb.mass * rbToAttract.mass) / Mathf.Pow(distance, 2);
    Vector3 force = direction.normalized * forceMagnitude;

    rbToAttract.AddForce(force);
}
2

If you want correct physics, I suggest not doing this and just decreasing the mass of the objects so that they naturally attract from further away. If you don’t care whether it’s physically correct or not, I suggest just changing the fixed update code to say this:

 foreach (Attractor attractor in Attractors)
     {
         if (attractor != this && (rb.position - attractor.rb.position).magnitude <= *REACH DISTANCE*)
         Attract(attractor);
     }