[vtkusers] vtkGeometryFilter for quadratic tetra grids

[kenichiro yoshimi]

Hi,

Could you provide some more information on what happens in applying
vtkGeometryFilter to quadratic tetra grids. At least, the following
simple code works without any problem using vtk 7.1.1.

---
import vtk

def main():

  points = vtk.vtkPoints()
  points.InsertNextPoint(0, 0, 0)
  points.InsertNextPoint(1, 0, 0)
  points.InsertNextPoint(1, 1, 0)
  points.InsertNextPoint(0.5, 0.5, 0.5)
  points.InsertNextPoint(0.5, 0, 0)
  points.InsertNextPoint(1, 0.5, 0)
  points.InsertNextPoint(0.5, 0.5, 0)
  points.InsertNextPoint(0.25, 0.25, 0.25)
  points.InsertNextPoint(0.75, 0.25, 0.25)
  points.InsertNextPoint(0.75, 0.75, 0.25)

  unstructuredGrid = vtk.vtkUnstructuredGrid()
  unstructuredGrid.SetPoints(points)

  quadraticTetra = vtk.vtkQuadraticTetra()

  for i in range(10):
    quadraticTetra.GetPointIds().SetId(i, i)

  cellArray = vtk.vtkCellArray()
  cellArray.InsertNextCell(quadraticTetra)

  unstructuredGrid.SetCells(vtk.VTK_QUADRATIC_TETRA, cellArray)

  print('quadraticTetra: ')
  print(' cell number: {}'.format(unstructuredGrid.GetNumberOfCells()))
  print(' point number: {}\n'.format(unstructuredGrid.GetNumberOfPoints()))

  geometryFilter = vtk.vtkGeometryFilter()
  geometryFilter.SetInputData(unstructuredGrid)
  geometryFilter.Update()

  print('extracted surface: ')
  print(' cell number:
{}'.format(geometryFilter.GetOutput().GetNumberOfCells()))
  print(' point number:
{}'.format(geometryFilter.GetOutput().GetNumberOfPoints()))

  mapper = vtk.vtkPolyDataMapper()
  mapper.SetInputConnection(geometryFilter.GetOutputPort())

  actor = vtk.vtkActor()
  actor.SetMapper(mapper)
  actor.GetProperty().EdgeVisibilityOn()

  renderer = vtk.vtkRenderer()
  renderer.AddActor(actor)

  renderer.ResetCamera()
  renderer.GetActiveCamera().Azimuth(210)
  renderer.GetActiveCamera().Elevation(30)

  renderWindow = vtk.vtkRenderWindow()
  renderWindow.SetSize(640, 480)
  renderWindow.AddRenderer(renderer)

  renderWindowInteractor = vtk.vtkRenderWindowInteractor()
  renderWindowInteractor.SetRenderWindow(renderWindow)

  renderWindowInteractor.Start()


if __name__ == '__main__':
    main()
---

Regards,
2018年8月18日(土) 4:17 Nguyen, Giang Hoang <ghnguyen at wpi.edu>:
>
> Hi,
>
>
> I would like to confirm here if vtkGeometryFilter doesn't work for unstructured grids that are quadratic tetra (10 nodes per cell). I was using it to convert an unstructured grid to polydata, using vtkpython in conda environment. The exact code works fine for unstructured grids with triangle cells. I looked at the cxx source for vtkGeometryFilter at https://github.com/Kitware/VTK/blob/master/Filters/Geometry/vtkGeometryFilter.cxx and it seems like the quadratic cells are not supported? In that case, what other approaches should I look into? Thanks in advance.
>
>
> Best,
>
> Giang
>
>
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html
>
> Please keep messages on-topic and check the VTK FAQ at: http://www.vtk.org/Wiki/VTK_FAQ
>
> Search the list archives at: http://markmail.org/search/?q=vtkusers
>
> Follow this link to subscribe/unsubscribe:
> https://public.kitware.com/mailman/listinfo/vtkusers