diff --git a/geomdl/NURBS.py b/geomdl/NURBS.py
index 0509a465..8b3ce8c0 100644
--- a/geomdl/NURBS.py
+++ b/geomdl/NURBS.py
@@ -91,9 +91,11 @@ def __deepcopy__(self, memo):
         result.init_cache()
         return result
 
-    def init_cache(self):
-        self._cache['ctrlpts'] = self._init_array()
-        self._cache['weights'] = self._init_array()
+    def init_cache(self, ctrlpts=[], weights=[]):
+        self._cache['ctrlpts'] = self._array_type(iter(ctrlpts))
+        self._cache['weights'] = self._array_type(iter(weights))
+        self._cache['ctrlpts'].register_callback(lambda: setattr(self, '_control_points_valid', False))
+        self._cache['weights'].register_callback(lambda: setattr(self, '_control_points_valid', False))
 
     @property
     def ctrlptsw(self):
@@ -107,6 +109,9 @@ def ctrlptsw(self):
         :getter: Gets the weighted control points
         :setter: Sets the weighted control points
         """
+        if not self._control_points_valid:
+            ctrlptsw = compatibility.combine_ctrlpts_weights(self.ctrlpts, self.weights)
+            self.set_ctrlpts(ctrlptsw)
         return self._control_points
 
     @ctrlptsw.setter
@@ -127,22 +132,17 @@ def ctrlpts(self):
         # Populate the cache, if necessary
         if not self._cache['ctrlpts']:
             c, w = compatibility.separate_ctrlpts_weights(self._control_points)
-            self._cache['ctrlpts'] = self._array_type(iter(c))
-            self._cache['weights'] = self._array_type(iter(w))
+            self.init_cache(c, w)
         return self._cache['ctrlpts']
 
     @ctrlpts.setter
     def ctrlpts(self, value):
         # Check if we can retrieve the existing weights. If not, generate a weights vector of 1.0s.
         if not self.weights:
-            weights = [1.0 for _ in range(len(value))]
-        else:
-            weights = self.weights
+            self.weights[:] = [1.0 for _ in range(len(value))]
 
         # Generate weighted control points using the new control points
-        ctrlptsw = compatibility.combine_ctrlpts_weights(value, weights)
-
-        # Set new weighted control points
+        ctrlptsw = compatibility.combine_ctrlpts_weights(value, self.weights)
         self.set_ctrlpts(ctrlptsw)
 
     @property
@@ -159,8 +159,7 @@ def weights(self):
         # Populate the cache, if necessary
         if not self._cache['weights']:
             c, w = compatibility.separate_ctrlpts_weights(self._control_points)
-            self._cache['ctrlpts'] = self._array_type(iter(c))
-            self._cache['weights'] = self._array_type(iter(w))
+            self.init_cache(c, w)
         return self._cache['weights']
 
     @weights.setter
@@ -174,6 +173,12 @@ def weights(self, value):
         # Set new weighted control points
         self.set_ctrlpts(ctrlptsw)
 
+    def _check_variables(self):
+        super(Curve, self)._check_variables()
+        if not self._control_points_valid:
+            ctrlptsw = compatibility.combine_ctrlpts_weights(self.ctrlpts, self.weights)
+            self.set_ctrlpts(ctrlptsw)
+
     def reset(self, **kwargs):
         """ Resets control points and/or evaluated points.
 
@@ -189,11 +194,9 @@ def reset(self, **kwargs):
         # Call parent function
         super(Curve, self).reset(ctrlpts=reset_ctrlpts, evalpts=reset_evalpts)
 
+        # Delete the caches
         if reset_ctrlpts:
-            # Delete the caches
-            self._cache['ctrlpts'] = self._init_array()
-            # TODO: why is this reset differently from the initialisation?
-            self._cache['weights'][:] = self._init_array()
+            self.init_cache()
 
 
 @export
diff --git a/geomdl/abstract.py b/geomdl/abstract.py
index 8ee0f171..ebb0c9cc 100644
--- a/geomdl/abstract.py
+++ b/geomdl/abstract.py
@@ -135,6 +135,7 @@ def __init__(self, **kwargs):
         self._knot_vector = [self._init_array() for _ in range(self._pdim)]  # knot vector
         self._control_points = self._init_array()  # control points
         self._control_points_size = [0 for _ in range(self._pdim)]  # control points length
+        self._control_points_valid = False
         self._delta = [self._dinit for _ in range(self._pdim)]  # evaluation delta
         self._bounding_box = self._init_array()  # bounding box
         self._evaluator = None  # evaluator instance
@@ -466,7 +467,7 @@ def validate_and_clean(pts_in, check_for, dimension, pts_out, **kws):
             raise ValueError("Number of arguments after ctrlpts must be " + str(self._pdim))
 
         # Keyword arguments
-        array_init = kwargs.get('array_init', [[] for _ in range(len(ctrlpts))])
+        array_init = kwargs.get('array_init', self._array_type([] for _ in range(len(ctrlpts))))
         array_check_for = kwargs.get('array_check_for', (list, tuple))
         callback_func = kwargs.get('callback', validate_and_clean)
         self._dimension = kwargs.get('dimension', len(ctrlpts[0]))
@@ -480,6 +481,7 @@ def validate_and_clean(pts_in, check_for, dimension, pts_out, **kws):
         # Set control points and sizes
         self._control_points = callback_func(ctrlpts, array_check_for, self._dimension, array_init, **kwargs)
         self._control_points_size = [int(arg) for arg in args]
+        self._control_points_valid = True
 
     @abc.abstractmethod
     def render(self, **kwargs):
@@ -891,6 +893,7 @@ def reset(self, **kwargs):
         if reset_ctrlpts:
             self._control_points = self._init_array()
             self._bounding_box = self._init_array()
+            self._control_points_valid = False
 
         if reset_evalpts:
             self._eval_points = self._init_array()