diff --git a/processing/pre/spectral_voronoiTessellation.py b/processing/pre/spectral_voronoiTessellation.py
index 709f08a81..2861bd05a 100755
--- a/processing/pre/spectral_voronoiTessellation.py
+++ b/processing/pre/spectral_voronoiTessellation.py
@@ -88,10 +88,10 @@ for file in files:
        
       if lineCount==headCount:  # all header info there, allocating arrays
         if resolution[2]==1: spatialDim=2
-        validDim    = numpy.zeros(spatialDim)
+        validDim    = numpy.zeros(3)
         dimension   = numpy.zeros(3)
-        for i,j in zip (xrange(3),xrange(spatialDim)):
-          if(options.dimension[i]>0): validDim[j]= 1
+        for i in xrange(3):
+          if(options.dimension[i]>0): validDim[i]= 1
         for i in xrange(3):  
           if(any(validDim) and options.dimension[i]==0): 
             dimension[i] = max(numpy.array(options.dimension,dtype='float')/resolution) *resolution[i]