Преобразование класса Point

Подскажите пожалуйста, как сделать преобразование класса points2Dcalc1 в класс Point, компилятор ошибку выдает из-за несовпадения типов. Инициализировать весь массив points2Dcalc_complex не могу, потому что три разных класса

        Point[] points2Dcalc_complex = new Point[12];                 
        private void points2Dcomplex() 
    {
        points2Dcalc_complex[0] = new points2Dcalc1(points3D[0].x, points3D[0].y);
        points2Dcalc_complex[1] = new points2Dcalc1(points3D[1].x, points3D[1].y); //1Tx
        points2Dcalc_complex[2] = new points2Dcalc2(points3D[3].x, points3D[3].z); //2Tz
        points2Dcalc_complex[3] = new points2Dcalc1(points3D[2].x, points3D[2].y); //1Ty1
        points2Dcalc_complex[4] = new points2Dcalc3(points3D[2].y, points3D[2].z); //3Ty2
        points2Dcalc_complex[5] = new points2Dcalc1(points3D[4].x, points3D[4].y); //1T1
        points2Dcalc_complex[6] = new points2Dcalc2(points3D[5].x, points3D[5].z); //2T2
        points2Dcalc_complex[7] = new points2Dcalc3(points3D[6].y, points3D[6].z); //3T3
        points2Dcalc_complex[8] = new points2Dcalc1(points3D[9].x, points3D[9].y); //1начало x
        points2Dcalc_complex[9] = new points2Dcalc2(points3D[13].x, points3D[13].z); //2z
        points2Dcalc_complex[10] = new points2Dcalc1(points3D[11].x, points3D[11].y); //1y1
        points2Dcalc_complex[11] = new points2Dcalc3(points3D[11].y, points3D[11].z); //3y2   
    }
    public class points2Dcalc1
    {
        public int X, Y;
        public points2Dcalc1(int _x, int _y)
        {
            Form1 form1 = new Form1();
            int _oX = form1.oX;
            int _oY = form1.oY;
            X = _oX - _x;
            Y = _oY + _y;
        }
    }