Q:

Trying to save vtk files with tvtk made from NumPy arrays

I'm trying to use tvtk (the package included with Enthought's Canopy) to turn some arrays into .vtk data that I can toss over to VisIt (mayavi complains on my OS (Mac OS X). I found what looked like the solution here (Exporting a 3D numpy to a VTK file for viewing in Paraview/Mayavi) but I'm not recovering the output that the author of the answer does and was wondering if anyone could tell me what I'm doing wrong. So I enter the commands in the Canopy notebook,
import numpy as np
from enthought.tvtk.api import tvtk, write_data

data = np.random.random((10,10,10))

grid = tvtk.ImageData(spacing=(10, 5, -10), origin=(100, 350, 200), 
                  dimensions=data.shape)
grid.point_data.scalars = np.ravel([], order='F')
grid.point_data.scalars.name = 'Test Data'

# Writes legacy ".vtk" format if filename ends with "vtk", otherwise
# this will write data using the newer xml-based format.
write_data(grid, '/Users/Epictetus/Documents/Dropbox/Work/vtktest.vtk')

which does create a vtk file, but unlike the output the author of the previous answer suggests, I just get a blank output,
# vtk DataFile Version 3.0
vtk output
ASCII
DATASET STRUCTURED_POINTS
DIMENSIONS 10 10 10
SPACING 10 5 -10
ORIGIN 100 350 200

Is it obvious what I'm doing wrong? File I/O has never been my forte...
Cheers!
-user2275987

A:

Change the line 
grid.point_data.scalars = np.ravel([], order='F')

to
grid.point_data.scalars = data.ravel(order='F')

Your grid doesn't have any data, and hence nothing is saved to the vtk file! :-)

