Accidentally created anti-gravity while trying to create faux gravity?

Unity Engine
,
1

Hey all, trying to create a sort of faux gravity that will allow my player character to walk around a 3D sphere (like a small planet). Currently, whenever play the scene the player character flies away from the planet as opposed to being attracted to it and I can’t seem to figure out why.

This script goes on the player character, who has a Rigidbody with gravity off:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class FauxGravityBody : MonoBehaviour
{
    public FauxGravityAttractor attractor;
    private Transform myTransform;
   
    void Start()
    {
        GetComponent<Rigidbody>().constraints = RigidbodyConstraints.FreezeRotation;
        GetComponent<Rigidbody>().useGravity = false;
        myTransform = transform;
    }

    void Update()
    {
        attractor.Attract(myTransform);
    }
}

And this code is set on the planet:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class FauxGravityAttractor : MonoBehaviour
{

    public float gravity = -10;
    public void Attract(Transform body)
    {
        Vector3 gravityUp = (body.position - transform.position).normalized;
        Vector3 bodyUp = body.up;

        body.GetComponent<Rigidbody>().AddForce(gravityUp * gravity);

        Quaternion targetRotation = Quaternion.FromToRotation(bodyUp, gravityUp) * body.rotation;
        body.rotation = Quaternion.Slerp(body.rotation, targetRotation, 50 * Time.deltaTime);
    }
}

Any idea what I’m doing wrong here? As I understand it the planet should have an attractive force on the player character, but instead I have a repulsive force (that is admittedly sending it flying hilariously fast away)

2

Slight update:

I’ve found that based on slightly different initial placements of the player character that it will sometimes orbit the planet instead of being sent flying away from it. Good new is I’ve confirmed that the part of the script that keeps the player character upright by modifying it’s rotation works, bad news is I still can’t get it to walk across the surface of the planet

3

Well for starters, you’re adding forces per-frame so the forces change in relation to frame-rate. Those forces won’t be used until the physics runs which is per fixed-update by default unless you’re running them per-frame.

You’re also referencing Transform.position (ugh, what is it with everyone always using Transform??) when the Rigidbody.position/rotation is authoritative. They also won’t be the same if you’re using interpolation.