diff --git a/lib/damask/__init__.py b/lib/damask/__init__.py
index bd8cecfb1..1018b44a1 100644
--- a/lib/damask/__init__.py
+++ b/lib/damask/__init__.py
@@ -5,6 +5,7 @@ from .environment import Environment      # only one class
 from .asciitable  import ASCIItable       # only one class
 from .config      import Material         # will be extended to debug and numerics
 from .colormaps   import Colormap, Color
+from .orientation import Vector3, Quaternion
 #from .block       import Block           # only one class
 from .result      import Result           # one class with subclasses
 from .geometry    import Geometry         # one class with subclasses
@@ -51,4 +52,4 @@ except (ImportError,AttributeError) as e:
                                           ):
     sys.stderr.write('\nWARNING: Core module (Fortran code) not available, \n'\
                      'try to run setup_processing.sh or compile_CoreModule.py\n'\
-                     'Error Message when importing core.so: %s\n\n'%e)
+                     'Error message when importing core.so: %s\n\n'%e)
diff --git a/lib/orientation.py b/lib/damask/orientation.py
similarity index 97%
rename from lib/orientation.py
rename to lib/damask/orientation.py
index c4f068dfb..606b9c2bb 100644
--- a/lib/orientation.py
+++ b/lib/damask/orientation.py
@@ -244,11 +244,17 @@ class Vector3:
                         self.z - d * normal[2]])
 
     def inSST(self,symmetry):
-        return {'cubic':       lambda R: R.inFZ('cubic')       and R.x >= R.y and R.y >= R.z and R.z >= 0.0,
-                'hexagonal':   lambda R: R.inFZ('hexagonal')   and R.x >= math.sqrt(3)*R.y and R.y >= 0.0 and R.z >= 0.0,
-                'tetragonal':  lambda R: R.inFZ('tetragonal')  and R.x >= R.y and R.y >= 0.0 and R.z >= 0.0,
-                'orthorombic': lambda R: R.inFZ('orthorombic') and R.x >= 0.0 and R.y >= 0.0 and R.z >= 0.0,
-               }.get(symmetry.lower(),False)(self)
+      '''
+      Determination of disorientations follow the work of A. Heinz and P. Neumann:
+      Representation of Orientation and Disorientation Data for
+      Cubic, Hexagonal, Tetragonal and Orthorhombic Crystals
+      Acta Cryst. (1991). A47, 780-789
+      '''
+      return {'cubic':       lambda R: R.inFZ('cubic')       and R.x >= R.y and R.y >= R.z and R.z >= 0.0,
+              'hexagonal':   lambda R: R.inFZ('hexagonal')   and R.x >= math.sqrt(3)*R.y and R.y >= 0.0 and R.z >= 0.0,
+              'tetragonal':  lambda R: R.inFZ('tetragonal')  and R.x >= R.y and R.y >= 0.0 and R.z >= 0.0,
+              'orthorombic': lambda R: R.inFZ('orthorombic') and R.x >= 0.0 and R.y >= 0.0 and R.z >= 0.0,
+             }.get(symmetry.lower(),False)(self)
 
     def inFZ(self,symmetry):
         return {'cubic':       lambda R:     math.sqrt(2.0)-1.0 >= abs(R.x) \