VTK/Examples/Cxx/StructuredPoints/StructuredPointsToUnstructuredGrid

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StructuredPointsToUnstructuredGrid.cxx

#include <vtkSmartPointer.h>
#include <vtkStructuredPoints.h>
#include <vtkXMLUnstructuredGridWriter.h>
#include <vtkUnstructuredGrid.h>

int main(int argc, char *argv[])
{
  // Create a structuredpoints
  vtkSmartPointer<vtkStructuredPoints> structuredPoints = 
    vtkSmartPointer<vtkStructuredPoints>::New();
  
  // Specify the size of the image data
  structuredPoints->SetDimensions(2,3,1);
  structuredPoints->SetNumberOfScalarComponents(1);
  structuredPoints->SetScalarTypeToDouble();
  
  int* dims = structuredPoints->GetDimensions();
    
  std::cout << "Dims: " << " x: " << dims[0] << " y: " << dims[1] << " z: " << dims[2] << std::endl;
  
  std::cout << "Number of points: " << structuredPoints->GetNumberOfPoints() << std::endl;
  std::cout << "Number of cells: " << structuredPoints->GetNumberOfCells() << std::endl;
  
  //fill every entry of the image data with "2.0"
  for (int z = 0; z < dims[2]; z++)
    {
    for (int y = 0; y < dims[1]; y++)
      {
      for (int x = 0; x < dims[0]; x++)
        {
        double* pixel = static_cast<double*>(structuredPoints->GetScalarPointer(x,y,z));
        pixel[0] = 2.0;
        }
      }
    }
  
  
  // Copy the points from the StructuredPoints to the UnstructuredGrid
  vtkSmartPointer<vtkPoints> points = 
    vtkSmartPointer<vtkPoints>::New();
  
  //retrieve the entries from the grid and print them to the screen
  unsigned int counter = 0;
  for(vtkIdType i = 0; i < structuredPoints->GetNumberOfPoints(); i++)
    {
    double p[3];
    structuredPoints->GetPoint(i, p);
    
    points->InsertNextPoint(p);
    }
  
  vtkSmartPointer<vtkUnstructuredGrid> ug = 
    vtkSmartPointer<vtkUnstructuredGrid>::New();
  ug->SetPoints(points);
  
  vtkSmartPointer<vtkXMLUnstructuredGridWriter> writer = 
    vtkSmartPointer<vtkXMLUnstructuredGridWriter>::New();
  writer->SetFileName("output.vtu");
  writer->SetInput(ug);
  writer->Write();
  
  return EXIT_SUCCESS;
}

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CMakeLists.txt

cmake_minimum_required(VERSION 2.8)

PROJECT(StructuredPointsToUnstructuredGrid)

find_package(VTK REQUIRED)
include(${VTK_USE_FILE})

add_executable(StructuredPointsToUnstructuredGrid MACOSX_BUNDLE StructuredPointsToUnstructuredGrid.cxx)

if(VTK_LIBRARIES)
  target_link_libraries(StructuredPointsToUnstructuredGrid ${VTK_LIBRARIES})
else()
  target_link_libraries(StructuredPointsToUnstructuredGrid vtkHybrid vtkWidgets)
endif()

Download and Build StructuredPointsToUnstructuredGrid

Click here to download StructuredPointsToUnstructuredGrid. and its CMakeLists.txt file.

Once the tarball StructuredPointsToUnstructuredGrid.tar has been downloaded and extracted,

cd StructuredPointsToUnstructuredGrid/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:

./StructuredPointsToUnstructuredGrid

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