Getting the samples out of vtkProbeFilter ...

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The issue is the ordering of numpy multidimensional arrays, and in particular the use of meshgrid.

Try switching your meshgrid around like this:

Z, Y, X = np.meshgrid(
    np.linspace(-0.012, 0.036, 21),  # Z space
    np.linspace(-0.006, 0.027, 21),  # Y space
    np.linspace( 0.120, 0.225, 51),  # X space
    indexing='ij')

If your meshgrid is built correctly, then when you print out the points, you should see the X values changing the most rapidly, followed by Y, and then followed by Z:

# Points:
#  0      1      2    ... 22488  22489  22490
[0.12   0.1221 0.1242 ... 0.2208 0.2229 0.225]  # X.ravel()
[-0.006 -0.006 -0.006 ... 0.027  0.027  0.027]  # Y.ravel()
[-0.012 -0.012 -0.012 ... 0.036  0.036  0.036]  # Z.ravel()

On the other hand, if Point 0 and Point 1 have the same X value, then you know that meshgrid has produced a grid that’s not ordered correctly for VTK.

Also be sure to switch around the numpy array dimensions before you use them in VTK:

z_size, y_size, x_size = X.shape
sg.SetDimensions(x_size, y_size, z_size)

Some people prefer to transpose the numpy arrays before using them with VTK, but I prefer to leave all the arrays in their original ordering, and just re-order the indices instead.

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