[vtkusers] Merging an example with my data

Nick Torenvliet natorenvliet at gmail.com
Thu Oct 19 20:45:51 EDT 2017


I am looking at the pointToCellData.py example.

In that example an unstructured grid reader opens a .vtk file and extracts
some named unstructured grid scalar and vector data like so...

reader = vtk.vtkUnstructuredGridReader()
reader.SetFileName(VTK_DATA_ROOT + "/Data/blow.vtk")
reader.SetScalarsName("thickness9")
reader.SetVectorsName("displacement9")

p2c = vtk.vtkPointDataToCellData()
p2c.SetInputConnection(reader.GetOutputPort())
p2c.PassPointDataOn()
warp = vtk.vtkWarpVector()
warp.SetInputConnection(p2c.GetOutputPort())
thresh = vtk.vtkThreshold()
thresh.SetInputConnection(warp.GetOutputPort())
thresh.ThresholdBetween(0.25, 0.75)
thresh.SetInputArrayToProcess(1, 0, 0, 0, "thickness9")


In the code I've written to front end this, I want to replace the reader
with my own method for extracting an unstructured grid like so...

gap_data_block, gap_file_info = getgap.get_gap_data_from_files(gap_file)
points = vtk.vtkPoints()
points.SetData(VN.numpy_to_vtk(gap_data_block, deep=True))
ugrid = vtk.vtkUnstructuredGrid()
ugrid.SetPoints(points)

Where gap_data_block is a numpy array of shape (n,3) carrying data for
dimensions are x/y/z.

Ultimately I want to get a surface elevation plot of gap_data_block by
working through the example code cited above.

As part of this (extremely) pedagogical experience, I feel I need to do two
things:

   1. Find a way to label columns one and two of get_data_block as a vector
   using some equivalent to reader.SetVectorsName()
   2. Find a way to label columns three of get_data_block as a scalar using
   some equivalent to reader.SetVectorsName()
   3. Find a way to set the input connection, or input data of a
   vtkPointDataToCellData object to my vtkUnstructuredGrid object ugrid.

I've been looking at this for a few hours now, any help getting my ugrid to
an elevation plot would be appreciated.

Thanks,

nt
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