diff --git a/processing/pre/geom_rotate.py b/processing/pre/geom_rotate.py
new file mode 100755
index 000000000..8c451a901
--- /dev/null
+++ b/processing/pre/geom_rotate.py
@@ -0,0 +1,146 @@
+#!/usr/bin/env python
+# -*- coding: UTF-8 no BOM -*-
+
+import os,sys,string,math
+import numpy as np
+import damask
+from scipy import ndimage
+from optparse import OptionParser
+
+scriptID   = string.replace('$Id$','\n','\\n')
+scriptName = os.path.splitext(scriptID.split()[1])[0]
+
+#--------------------------------------------------------------------------------------------------
+#                                MAIN
+#--------------------------------------------------------------------------------------------------
+
+parser = OptionParser(option_class=damask.extendableOption, usage='%prog options [file[s]]', description = """
+Rotates spectral geometry description.
+
+""", version=scriptID)
+
+parser.add_option('-r', '--rotation',
+                  dest='rotation',
+                  type = 'float', nargs = 4, metavar = ' '.join(['float']*4),
+                  help = 'rotation given as angle and axis')
+parser.add_option('-e', '--eulers',
+                  dest = 'eulers',
+                  type = 'float', nargs = 3, metavar = ' '.join(['float']*3),
+                  help = 'rotation given as Euler angles')
+parser.add_option('-d', '--degrees',
+                  dest = 'degrees',
+                  action = 'store_true',
+                  help = 'Euler angles are given in degrees [%default]')
+parser.add_option('-m', '--matrix',
+                  dest = 'matrix',
+                  type = 'float', nargs = 9, metavar = ' '.join(['float']*9),
+                  help = 'rotation given as matrix')
+parser.add_option('-q', '--quaternion',
+                  dest = 'quaternion',
+                  type = 'float', nargs = 4, metavar = ' '.join(['float']*4),
+                  help = 'rotation given as quaternion')
+parser.add_option('-f', '--fill',
+                  dest = 'fill',
+                  type = 'int', metavar = 'int',
+                  help = 'background grain index. "0" selects maximum microstructure index + 1 [%default]')
+
+parser.set_defaults(degrees = False,
+                    fill = 0)
+
+(options, filenames) = parser.parse_args()
+
+if sum(x != None for x in [options.rotation,options.eulers,options.matrix,options.quaternion]) !=1:
+  parser.error('not exactly one rotation specified...')
+
+toRadian = math.pi/180. if options.degrees else 1.0
+eulers = np.array(damask.orientation.Orientation(
+                         quaternion=np.array(options.quaternion)      if options.quaternion else None,
+                         angleAxis =np.array(options.rotation)        if options.rotation else None,
+                         matrix    =np.array(options.matrix)          if options.matrix else None,
+                         Eulers    =np.array(options.eulers)*toRadian if options.eulers else None
+                  ).asEulers()) *180./math.pi
+
+# --- loop over input files -------------------------------------------------------------------------
+
+if filenames == []: filenames = [None]
+
+for name in filenames:
+  try:
+    table = damask.ASCIItable(name = name,
+                              buffered = False, labeled = False)
+  except: continue
+  damask.util.report(scriptName,name)
+
+# --- interpret header ----------------------------------------------------------------------------
+
+  table.head_read()
+  info,extra_header = table.head_getGeom()
+
+  damask.util.croak(['grid     a b c:  %s'%(' x '.join(map(str,info['grid']))),
+                     'size     x y z:  %s'%(' x '.join(map(str,info['size']))),
+                     'origin   x y z:  %s'%(' : '.join(map(str,info['origin']))),
+                     'homogenization:  %i'%info['homogenization'],
+                     'microstructures: %i'%info['microstructures'],
+                    ])
+
+  errors = []
+  if np.any(info['grid'] < 1):    errors.append('invalid grid a b c.')
+  if np.any(info['size'] <= 0.0): errors.append('invalid size x y z.')
+  if errors != []:
+    damask.util.croak(errors)
+    table.close(dismiss = True)
+    continue
+
+# --- read data ------------------------------------------------------------------------------------
+
+  microstructure = table.microstructure_read(info['grid']).reshape(info['grid'],order='F')                    # read microstructure
+
+  newGrainID = options.fill if options.fill > 0 else microstructure.max()+1
+  microstructure = ndimage.rotate(microstructure,eulers[2],(0,1),order=0,output=np.dtype(int),cval=newGrainID) # rotation around Z
+  microstructure = ndimage.rotate(microstructure,eulers[1],(1,2),order=0,output=np.dtype(int),cval=newGrainID) # rotation around X
+  microstructure = ndimage.rotate(microstructure,eulers[0],(0,1),order=0,output=np.dtype(int),cval=newGrainID) # rotation around Z
+
+# --- do work ------------------------------------------------------------------------------------
+
+  newInfo = {
+             'size':   microstructure.shape*info['size']/info['grid'],
+             'grid':   microstructure.shape,
+             'microstructures': microstructure.max(),
+            }
+
+
+# --- report ---------------------------------------------------------------------------------------
+
+  remarks = []
+  if (any(newInfo['grid']            != info['grid'])):
+    remarks.append('--> grid    a b c:  %s'%(' x '.join(map(str,newInfo['grid']))))
+  if (any(newInfo['size']            != info['size'])):
+    remarks.append('--> size    x y z:  %s'%(' x '.join(map(str,newInfo['size']))))
+  if (    newInfo['microstructures'] != info['microstructures']): 
+    remarks.append('--> microstructures: %i'%newInfo['microstructures'])
+  if remarks != []: damask.util.croak(remarks)
+
+# --- write header ---------------------------------------------------------------------------------
+
+  table.labels_clear()
+  table.info_clear()
+  table.info_append([
+    scriptID + ' ' + ' '.join(sys.argv[1:]),
+    "grid\ta {grid[0]}\tb {grid[1]}\tc {grid[2]}".format(grid=newInfo['grid']),
+    "size\tx {size[0]}\ty {size[1]}\tz {size[2]}".format(size=newInfo['size']),
+    "origin\tx {origin[0]}\ty {origin[1]}\tz {origin[2]}".format(origin=info['origin']),
+    "homogenization\t{homog}".format(homog=info['homogenization']),
+    "microstructures\t{microstructures}".format(microstructures=newInfo['microstructures']),
+    extra_header
+    ])
+  table.head_write()
+
+# --- write microstructure information ------------------------------------------------------------
+
+  formatwidth = int(math.floor(math.log10(microstructure.max())+1))
+  table.data = microstructure.reshape((newInfo['grid'][0],np.prod(newInfo['grid'][1:])),order='F').transpose()
+  table.data_writeArray('%%%ii'%(formatwidth),delimiter = ' ')
+
+# --- output finalization --------------------------------------------------------------------------
+
+  table.close()                                                                                     # close ASCII table