code: @Override
  	public Point3d getGeometricCenter() {
  		run();
  
  		Point3d geometricCenter = new Point3d();
  		Vector3d translation = new Vector3d();
  		reverseTransformationMatrix.get(translation);
  
  		// calculate adjustment around z-axis and transform adjustment to
  		//  original coordinate frame with the reverse transformation
  		if (rotationGroup.getPointGroup().startsWith("C")) {
  			Vector3d corr = new Vector3d(0,0, minBoundary.z+getDimension().z);
  			reverseTransformationMatrix.transform(corr);
  			geometricCenter.set(corr);
  		}
  
  		geometricCenter.add(translation);
  		return geometricCenter;
  	}
docs: Returns the geometric center of polyhedron. In the case of the Cn
  point group, the centroid and geometric center are usually not
  identical.
  @return