diff --git a/src/borders.py b/src/borders.py
index b714d3d..27e9d43 100644
--- a/src/borders.py
+++ b/src/borders.py
@@ -2,11 +2,11 @@ import numpy as np
 import matplotlib.pyplot as plt
 
 
-def update_border(voxel_values, xy=None):
+def update_border(voxel_values, idx=None):
 
     voxel_values = voxel_values > 0
 
-    if xy is None:
+    if idx is None:
         x_m1 = voxel_values[1:, :, :]
         x_m1 = np.concatenate((x_m1, np.zeros((1, x_m1.shape[1], x_m1.shape[2]))), axis=0)
 
@@ -29,6 +29,8 @@ def update_border(voxel_values, xy=None):
                                      voxel_values != y_m1, voxel_values != y_p1,
                                      voxel_values != z_m1, voxel_values != z_p1))
 
+    # TODO: update only concidered voxels (idx)
+
 
 if __name__ == '__main__':
     voxel_values = np.array([[[np.sqrt(x**2 + y**2 + z**2) < 20 for z in np.arange(-10, 10, 1.0)] for y in np.arange(-10, 10, 1.0)] for x in np.arange(-10, 10, 1.0)])