How to convert 3D numpy array to vtk and save the .vtk file?

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yes you are right.

import vtk.util.numpy_support as numpy_support

def numpyToVTK(data):
    data_type = vtk.VTK_FLOAT
    shape = data.shape

    flat_data_array = data.flatten()
    vtk_data = numpy_support.numpy_to_vtk(num_array=flat_data_array, deep=True, array_type=data_type)
    
    img = vtk.vtkImageData()
    img.GetPointData().SetScalars(vtk_data)
    img.SetDimensions(shape[0], shape[1], shape[2])
    return img

with the above function I did a quick test below:

test_arr = np.arange(36).reshape(3,4,3)
test_arr

--> array([[
        [ 0,  1,  2],
        [ 3,  4,  5],
        [ 6,  7,  8],
        [ 9, 10, 11]],

       [[12, 13, 14],
        [15, 16, 17],
        [18, 19, 20],
        [21, 22, 23]],

       [[24, 25, 26],
        [27, 28, 29],
        [30, 31, 32],
        [33, 34, 35]]])

img = numpyToVTK(data)

Then verify the vtkImageData is right or not

test = vtk.util.numpy_support.vtk_to_numpy(img.GetPointData().GetScalars())
test = test.reshape(3,4,3)
(test == test_arr).all()

-->True

However,I’m like you and don’t know how to save the vtk file to the hard drive

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