diff --git a/openptv_python/calibration.py b/openptv_python/calibration.py
index bb59f8e..a0a7077 100644
--- a/openptv_python/calibration.py
+++ b/openptv_python/calibration.py
@@ -100,27 +100,6 @@ def set_back_focal_distance(self, cc: float) -> None:
         """Set the back focal distance of the camera."""
         self.cc = cc
 
-
-# class Glass:
-#     """Glass data structure."""
-
-#     def __init__(self, vec_x=0.0, vec_y=0.0, vec_z=1.0):
-#         self.vec_x = vec_x
-#         self.vec_y = vec_y
-#         self.vec_z = vec_z
-
-#     def set_glass_vec(self, vec: np.ndarray) -> None:
-#         """Set the glass vector."""
-#         self.vec_x, self.vec_y, self.vec_z = vec
-
-Glass_dtype = np.dtype(
-    [
-        ("vec_x", np.float64),
-        ("vec_y", np.float64),
-        ("vec_z", np.float64),
-    ]
-)
-
 def default_glass_vec() -> np.ndarray:
     """Return default glass vector."""
     return vec_set(0.0, 0.0, 1.0)
@@ -174,7 +153,7 @@ def __init__(self, ext_par=None, int_par=None, glass_par=None, added_par=None, m
         if int_par is None:
             int_par = Interior()
         if glass_par is None:
-            glass_par = default_glass_vec()
+            glass_par = np.array([0.0, 0.0, 1.0])
         if added_par is None:
             added_par = ap_52()
         if mmlut is None:
@@ -418,7 +397,7 @@ def set_glass_vec(self, gvec: np.ndarray):
         self.glass_par = gvec
 
     def get_glass_vec(self) -> np.ndarray:
-        """Return the glass vector, a 3-element array of Glass_dtype."""
+        """Return the glass vector, a 3-element array of float."""
         return self.glass_par
 
     def set_added_par(self, listpar: np.ndarray | list):
@@ -518,8 +497,8 @@ def compare_glass(g1: np.ndarray, g2: np.ndarray) -> bool:
 
     Args:
     ----
-        g1 (Glass_dtype): vector pointing from the 3D origin to the surface of the glass
-        g2 (Glass_dtype): another vector for comparison
+        g1 (float array): vector pointing from the 3D origin to the surface of the glass
+        g2 (float array): another vector for comparison
 
     Returns
     -------
diff --git a/tests/test_multimedia_r_nlay.py b/tests/test_multimedia_r_nlay.py
index 710fb01..0cb8385 100644
--- a/tests/test_multimedia_r_nlay.py
+++ b/tests/test_multimedia_r_nlay.py
@@ -5,7 +5,6 @@
 from openptv_python.calibration import (
     Calibration,
     Exterior,
-    Glass_dtype,
     Interior,
     ap_52,
 )
@@ -29,7 +28,7 @@ def test_multimedia_r_nlay(self):
         )
 
         test_I = Interior(0.0, 0.0, 100.0)
-        test_G = np.array([(0.0001, 0.00001, 1.0)], dtype=Glass_dtype).view(np.recarray)
+        test_G = np.array((0.0001, 0.00001, 1.0))
         test_addp = ap_52(0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0)
         test_cal = Calibration(
             test_Ex, test_I, test_G, test_addp