Center Gravity in Unity

Question

a 2d planet in the center, where the players will be able to walk on it and also will be affected by center gravity. planet will be static and there won't be any other planets. so;

Is there a way that I can change the gravity position? yes you can adjust gravity via project settings but I want it to be in the middle x,y,z(0,0,0)

I have tried creating my own gravity but it wasn't very useful because objects wouldnt fall, stand on foot and also in contact with another object they would vibrate instead of standing still. (if they stand on the planet they would vibrate)

        private void FixedUpdate()
{
    foreach(GameObject item in grav)
    {
        Attact(item);
    }
}

private void Attact(GameObject gmf)
{
    Rigidbody2D rgg = gmf.GetComponent<Rigidbody2D>();

    Vector3 direction = rg2d.position - rgg.position;
    float distance = direction.sqrMagnitude;

    float forceMag = (10 * rgg.mass) / distance;
    Vector3 force = direction.normalized * forceMag * 10;

    rgg.AddForce(force);
}

I can create a script that will change the gravity by the opposite of the object's position. this does work but I cannot see any way to do it for more than one object.

Answer 1

Are you aware of the PointEffector2D component? I believe that is exactly what this is for.

See this tutorial (step 7). (Link directly to video)

Answer 2

You can't use the Unity gravity system for point gravity sources. As mentioned by the answer by Ed Marty, you can use the PointEffector2D component to create a point gravity source, but only if all your rigidbodies have the same mass.

But you can also very easily build your own gravity system. Here is an example script for a "Gravity Source" component. Place it at your center of gravity, set the "gravity" value in the inspector to your desired acceleration and give it a trigger-collider which represents the zone in which it is supposed to affect objects.

using UnityEngine;

public class GravitySource : MonoBehaviour {

    public float gravity;

    void OnTriggerStay2D(Collider2D other) {
        if (other.attachedRigidbody) {
            Vector2 difference = this.gameObject.transform.position - other.gameObject.transform.position;
            Vector2 gravityDirection = difference.normalized;
            Vector2 gravityVector = gravityDirection * gravity;

            other.attachedRigidbody.AddForce(gravityVector, ForceMode.Acceleration);    
        }
    }
}

This script is a simplified version of my script from my answer to the question "How can I accurately simulate orbits in Unity?". The more complicated version works with 3d rigidbodies and simulates gravity getting weaker with distance.

What this script does not do is tell the objects it affects where "down" is. Depending on your game you might want to rotate objects towards the center of gravity under some conditions. If you want to add this, then you can use the gravityDirection vector for this purpose.