diff --git a/main.py b/main.py
index c8a4369..8203aa2 100644
--- a/main.py
+++ b/main.py
@@ -2,43 +2,77 @@ from pathlib import Path
 
 import numpy
 from matplotlib import pyplot
+from matplotlib.figure import figaspect, SubplotParams
+from mpl_toolkits.mplot3d import Axes3D
 
 from transformations import calculate_rotation_matrix, centroid, convert_rotation_matrix_to_angles
 
 expected_points_file_path = Path('expected_points.txt')
 actual_points_file_path = Path('actual_points.txt')
 
-plot_3d = pyplot.figure().add_subplot(projection='3d')
+plot_3d: Axes3D = pyplot.figure(subplotpars=SubplotParams(0, 0, 1, 1, 0, 0),
+                                figsize=(10, 8)).add_subplot(projection='3d')
 
 
 def read_points_from_file(points_file_path: Path) -> numpy.ndarray:
+    """
+    Чтение пути из файла
+
+    :param points_file_path: путь к файлу
+    :return: Путь, вычитанный из файла
+
+    """
     with points_file_path.open('r') as points_file:
         return numpy.array([[float(coordinate) for coordinate in point_line.strip().split(' ')]
                             for point_line in points_file])
 
 
+def rsmd(first_path: numpy.ndarray, second_path: numpy.ndarray) -> float:
+    """
+    Расчёт среднеквадратичное отклонение между путями
+
+    :param first_path: первый путь
+    :param second_path: второй путь
+    :return: СКО
+
+    """
+    diff = first_path - second_path
+    return numpy.sqrt((diff * diff).sum() / first_path.shape[0])
+
+
 if __name__ == '__main__':
     expected_points = read_points_from_file(expected_points_file_path)
     actual_points = read_points_from_file(actual_points_file_path)
 
     plot_3d.plot(expected_points[:, 0], expected_points[:, 1], expected_points[:, 2],
-                 'o-', markersize=12, linewidth=3, label='Expected Points')
+                 's-k', markersize=12, linewidth=3,
+                 label='Expected Points')
     plot_3d.plot(actual_points[:, 0], actual_points[:, 1], actual_points[:, 2],
-                 'o-', markersize=12, linewidth=3, label='Actual Points')
+                 's-g', markersize=12, linewidth=3,
+                 label='Actual Points')
 
-    rotation_matrix = calculate_rotation_matrix(actual_points, expected_points)
-    angles = convert_rotation_matrix_to_angles(rotation_matrix)
+    for calculation_points_number in range(len(actual_points), 1, -1):
+        print(f"{15 * '='} Calc on {calculation_points_number:2} points {15 * '='}")
+        rotation_matrix = calculate_rotation_matrix(actual_points,
+                                                    expected_points,
+                                                    calculation_points_number=calculation_points_number)
+        angles = convert_rotation_matrix_to_angles(rotation_matrix)
 
-    actual_points_rotated = numpy.dot(actual_points, rotation_matrix)
+        actual_points_rotated = numpy.dot(actual_points, rotation_matrix)
 
-    offset = centroid(actual_points_rotated) - centroid(expected_points)
-    actual_points_converted = actual_points_rotated - offset
+        actual_points_for_offset = actual_points_rotated[:calculation_points_number]
+        expected_points_for_offset = expected_points[:calculation_points_number]
 
-    print(f"{angles = }")
-    print(f"offset = {tuple(offset)}")
+        offset = centroid(actual_points_for_offset) - centroid(expected_points_for_offset)
+        actual_points_converted = actual_points_rotated - offset
 
-    plot_3d.plot(actual_points_converted[:, 0], actual_points_converted[:, 1], actual_points_converted[:, 2],
-                 'o-', markersize=12, linewidth=3, label='Transformed actual points')
+        print(f"    {angles = }")
+        print(f"    offset = {tuple(offset)}")
+        print(f"    error = {rsmd(expected_points, actual_points_converted)}")
+
+        plot_3d.plot(actual_points_converted[:, 0], actual_points_converted[:, 1], actual_points_converted[:, 2],
+                     'o-', markersize=9, linewidth=3,
+                     label=f'Transformed actual points (on {calculation_points_number} points)')
 
     plot_3d.grid(True)
     plot_3d.tick_params(labelsize=15)
diff --git a/transformations.py b/transformations.py
index 33fe885..cc2af9d 100644
--- a/transformations.py
+++ b/transformations.py
@@ -1,4 +1,4 @@
-from typing import Tuple
+from typing import Optional, Tuple
 
 import numpy
 
@@ -10,19 +10,29 @@ def centroid(points: numpy.ndarray) -> numpy.ndarray:
 
 
 def calculate_rotation_matrix(actual_points: numpy.ndarray,
-                              expected_points: numpy.ndarray) -> numpy.ndarray:
+                              expected_points: numpy.ndarray,
+                              *,
+                              calculation_points_number: Optional[int] = None) -> numpy.ndarray:
     """
     Вычисление матрицы поворота, который необходим для приближения текущих точек к ожидаемым, на основе алгоритма Кабша
 
     :param actual_points: массив текущих точек
     :param expected_points: массив ожидаемых точек
+    :param calculation_points_number: число используемых для поворота точек
     :return: Матрица поворотов
 
     """
+    sliced_actual_points = actual_points[:calculation_points_number] \
+        if isinstance(calculation_points_number, int) \
+        else actual_points
+    sliced_expected_points = expected_points[:calculation_points_number] \
+        if isinstance(calculation_points_number, int) \
+        else expected_points
+
     # Для применения алгоритма Кабша необходимо,
     # чтобы центроиды обрабатываемых массивов точек совпадали с началом координат
-    centred_actual_points = actual_points - centroid(actual_points)
-    centred_expected_points = expected_points - centroid(expected_points)
+    centred_actual_points = sliced_actual_points - centroid(sliced_actual_points)
+    centred_expected_points = sliced_expected_points - centroid(sliced_expected_points)
 
     # Вычисляем матрицу кросс-ковариаций
     cross_covariance_matrix = numpy.dot(numpy.transpose(centred_actual_points), centred_expected_points)