GeometryFilter

VTKEx/Cxx/PolyData/GeometryFilter

Description

This example demonstrates how to convert an unstructured grid to a polydata. Currently nothing is done with the resulting polydata. If someone has a good data set that demonstrates the conversion, please let us know.

Question

If you have a simple question about this example contact us at VTKExProject If your question is more complex and may require extended discussion, please use the VTK Discourse Forum

Code

GeometryFilter.cxx

#include <vtkSmartPointer.h>
#include <vtkPolyData.h>
#include <vtkUnstructuredGrid.h>
#include <vtkCellArray.h>
#include <vtkGeometryFilter.h>
#include <vtkPointSource.h>

int main(int, char *[])
{ 
  vtkSmartPointer<vtkUnstructuredGrid> unstructuredGrid = 
    vtkSmartPointer<vtkUnstructuredGrid>::New();

  vtkSmartPointer<vtkGeometryFilter> geometryFilter = 
    vtkSmartPointer<vtkGeometryFilter>::New();
  geometryFilter->SetInputData(unstructuredGrid);
  geometryFilter->Update(); 

  vtkPolyData* polydata = geometryFilter->GetOutput();

  std::cout << "Output has " << polydata->GetNumberOfPoints() << " points." << std::endl;

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(GeometryFilter)

find_package(VTK COMPONENTS 
  vtkvtkCommonCore
  vtkvtkCommonDataModel
  vtkvtkFiltersGeometry
  vtkvtkFiltersSources QUIET)
if (NOT VTK_FOUND)
  message("Skipping GeometryFilter: ${VTK_NOT_FOUND_MESSAGE}")
  return ()
endif()
message (STATUS "VTK_VERSION: ${VTK_VERSION}")
if (VTK_VERSION VERSION_LESS "8.90.0")
  # old system
  include(${VTK_USE_FILE})
  add_executable(GeometryFilter MACOSX_BUNDLE GeometryFilter.cxx )
  target_link_libraries(GeometryFilter PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(GeometryFilter MACOSX_BUNDLE GeometryFilter.cxx )
  target_link_libraries(GeometryFilter PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS GeometryFilter
    MODULES ${VTK_LIBRARIES}
    )
endif ()

Download and Build GeometryFilter

Click here to download GeometryFilter and its CMakeLists.txt file. Once the tarball GeometryFilter.tar has been downloaded and extracted,

cd GeometryFilter/build

If VTK is installed:

cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

make

and run it:

./GeometryFilter

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.