Hello,
I am trying to convert a Gmsh (unstructured) mesh into a structured grid (VTI).
Below is a part of a question that I asked on the PyVista slack forum (before I was granted access to VTK’s discourse forum). The code is based on https://kitware.github.io/vtk-examples/site/Python/ExplicitStructuredGrid/LoadESGrid/, https://kitware.github.io/vtk-examples/site/Python/ExplicitStructuredGrid/CreateESGrid/ and https://kitware.github.io/vtk-examples/site/Python/IO/ReadUnstructuredGrid/. I could not upload the .msh file
import meshio
import vtkmodules.vtkRenderingOpenGL2
from vtkmodules.vtkCommonColor import vtkNamedColors
from vtkmodules.vtkFiltersCore import vtkUnstructuredGridToExplicitStructuredGrid
from vtkmodules.vtkIOXML import vtkXMLUnstructuredGridReader
from vtkmodules.vtkInteractionStyle import vtkInteractorStyleRubberBandPick
from vtkmodules.vtkRenderingCore import (
vtkActor,
vtkDataSetMapper,
vtkRenderWindow,
vtkRenderWindowInteractor,
vtkRenderer
)
# exported with Gmsh as VTK, then:
meshio.read("mat_gmsh_simple_mesh.vtk").write("mat_gmsh_simple_mesh.vtu")
reader = vtkXMLUnstructuredGridReader()
reader.SetFileName("mat_gmsh_simple_mesh.vtu")
reader.Update()
#
converter = vtkUnstructuredGridToExplicitStructuredGrid()
# converter.GlobalWarningDisplayOff() # hide VTK errors
converter.GlobalWarningDisplayOn()
converter.SetInputConnection(reader.GetOutputPort())
converter.SetInputArrayToProcess(0, 0, 0, 1, 'BLOCK_I')
converter.SetInputArrayToProcess(1, 0, 0, 1, 'BLOCK_J')
converter.SetInputArrayToProcess(2, 0, 0, 1, 'BLOCK_K')
converter.Update()
#
grid = converter.GetOutput()
grid.ComputeFacesConnectivityFlagsArray()
The error message is
( 6.617s) [ 57842B80]vtkUnstructuredGridToEx:81 ERR| vtkUnstructuredGridToExplicitStructuredGrid (0x561812d759a0): An ijk array has not be set using SetInputArrayToProcess, aborting.
( 6.617s) [ 57842B80] vtkExecutive.cxx:752 ERR| vtkCompositeDataPipeline (0x5618130e26e0): Algorithm vtkUnstructuredGridToExplicitStructuredGrid(0x561812d759a0) returned failure for request: vtkInformation (0x5618130ec1c0)
Debug: Off
Modified Time: 556
Reference Count: 1
Registered Events: (none)
Request: REQUEST_DATA
FROM_OUTPUT_PORT: 0
ALGORITHM_AFTER_FORWARD: 1
FORWARD_DIRECTION: 0
Process Python segmentation fault (core dumped)
Running software:
VTK 9.1.0, Python 3.10.8, Meshio 5.3.4, Arch Linux
Your help and time are much appreciated. Thanks!