Simple utility class to mirror Unity's transforms along global planes

MirrorUtils.cs

using UnityEngine;

public static class MirrorUtils
{
    public enum MirrorPlane
    {
        OXY = 0,
        OXZ,
        OYZ
    }

    public static void MirrorAlongPlane(Transform p_source, Transform p_target, MirrorPlane p_plane)
    {
        Vector3 l_pos = p_source.position;
        Quaternion l_rot = p_source.rotation;
        switch(p_plane)
        {
            case MirrorPlane.OXY:
            {
                l_pos.z *= -1f;
                Swap(ref l_rot.x, ref l_rot.z);
                Swap(ref l_rot.y, ref l_rot.w);
                l_rot.x *= -1f;
                l_rot.z *= -1f;
            }
            break;

            case MirrorPlane.OXZ:
            {
                l_pos.y *= -1f;
                Swap(ref l_rot.x, ref l_rot.y);
                Swap(ref l_rot.z, ref l_rot.w);
            }
            break;

            case MirrorPlane.OYZ:
            {
                l_pos.x *= -1f;
                l_rot.y *= -1f;
                l_rot.z *= -1f;
            }
            break;
        }

        p_target.position = l_pos;
        p_target.rotation = l_rot;
    }

    public static void Swap<T>(ref T a, ref T b)
    {
        T l_temp = a;
        a = b;
        b = l_temp;
    }
}