Help How to simulate Planet gravity

[wushuaiqi]

my code is

Code:

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

public class Test : MonoBehaviour
{
    ObiSolver solver;
    void Start()
    {
        solver = transform.GetComponent<ObiSolver>();
       
    }
    void Update()
    {
        Debug.Log(solver.transform.position);
       
    }
}

this script on the Obi Solver
but result always (0.0,0.0,0.0)
but rope is moving;
Did i make a mistake?