Removed restriction of using of clamped shapes

I thought that I have already fixed this restriction

geomdl/BSpline.py

@@ -476,8 +476,8 @@ def evaluate(self, **kwargs):
         .. note:: The evaluated surface points are stored in :py:attr:`~curvepts`.
 
         """
-        start = kwargs.get('start', 0.0)
-        stop = kwargs.get('stop', 1.0)
+        start = kwargs.get('start', self._knot_vector[self._degree])
+        stop = kwargs.get('stop', self._knot_vector[-(self._degree+1)])
 
         # Check if the input parameters are in the range
         utils.check_uv(start)
@@ -1836,10 +1836,10 @@ def evaluate(self, **kwargs):
         .. note:: The evaluated surface points are stored in :py:attr:`~surfpts`.
 
         """
-        start_u = kwargs.get('start_u', 0.0)
-        stop_u = kwargs.get('stop_u', 1.0)
-        start_v = kwargs.get('start_v', 0.0)
-        stop_v = kwargs.get('stop_v', 1.0)
+        start_u = kwargs.get('start_u', self._knot_vector_u[self._degree_u])
+        stop_u = kwargs.get('stop_u', self._knot_vector_u[-(self._degree_u+1)])
+        start_v = kwargs.get('start_v', self._knot_vector_v[self._degree_v])
+        stop_v = kwargs.get('stop_v', self._knot_vector_v[-(self._degree_v+1)])
         # Check if all the input parameters are in the range
         utils.check_uv(start_u, stop_u)
         utils.check_uv(start_v, stop_v)

geomdl/utilities.py

@@ -245,40 +245,13 @@ def check_knot_vector(degree=0, knot_vector=(), control_points_size=0, tol=0.001
     # Set up a return value
     ret_val = True
 
-    # A proper knot vector should have a knot vector starting with degree + 1 zeros
-    count = 0
-    start_knot = 0.0
+    # Check ascending order
+    prev_knot = knot_vector[0]
     for knot in knot_vector:
-        if count > degree:
-            break
-        if not abs(start_knot - knot) < tol:
+        if prev_knot > knot:
             ret_val = False
             break
-        count += 1
-
-    # A proper knot vector should have a knot vector ending with degree + 1 ones
-    if ret_val:
-        knot_vector.reverse()
-        count = 0
-        end_knot = 1.0
-        for knot in knot_vector:
-            if count > degree:
-                break
-            if not abs(end_knot - knot) < tol:
-                ret_val = False
-                break
-            count += 1
-
-        knot_vector.reverse()
-
-    # Check ascending order
-    if ret_val:
-        prev_knot = knot_vector[0]
-        for knot in knot_vector:
-            if prev_knot > knot:
-                ret_val = False
-                break
-            prev_knot = knot
+        prev_knot = knot
 
     return ret_val