pogo-stick-game/Assets/VisualiseCenterOfMass.cs

// CenterOfMassVisualizer.cs
using UnityEngine;

[ExecuteAlways]
[RequireComponent(typeof(Rigidbody))]
public class VisualiseCenterOfMass : MonoBehaviour
{
    [Header("Gizmo Settings")]
    public Color gizmoColor = Color.cyan;
    public float gizmoSize = 0.05f;
    public bool drawLineToOrigin = true;

    private Rigidbody _rb; 

    private void OnEnable()
    {
        _rb = GetComponent<Rigidbody>();
    }

    private void OnDrawGizmos()
    {
        if (_rb == null)
            _rb = GetComponent<Rigidbody>();
        if (_rb == null)
            return;

        // Rigidbody.centerOfMass is in local space
        var worldCom = _rb.transform.TransformPoint(_rb.centerOfMass);

        Gizmos.color = gizmoColor;
        Gizmos.DrawSphere(worldCom, gizmoSize);

        if (drawLineToOrigin)
        {
            Gizmos.DrawLine(_rb.transform.position, worldCom);
        }
    }
}