1  public static void GetMirror(this ObjectIdCollection ids, Point3d p1, Point3d p2, bool s, params Entity[] ents)2        {3            foreach (Entity ent in ents)4            {5                ids.Add(ent.Mirror(p1, p2, s));6            }7        }

1  public static ObjectId GetMirror(this Entity ent,Point3d p1, Point3d p2, bool s)2        {3            ObjectId obj = new ObjectId();4            obj=ent.Mirror(p1, p2, s);5            return obj;6        }