StructuredPointsToUnstructuredGrid

VTKExamples/Cxx/StructuredPoints/StructuredPointsToUnstructuredGrid

Code

StructuredPointsToUnstructuredGrid.cxx

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

int main(int, char *[])
{
  // Create a structuredpoints
  vtkSmartPointer<vtkStructuredPoints> structuredPoints =
    vtkSmartPointer<vtkStructuredPoints>::New();

  // Specify the size of the image data
  structuredPoints->SetDimensions(2,3,1);
  structuredPoints->AllocateScalars(VTK_DOUBLE,1);

  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
  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->SetInputData(ug);
  writer->Write();

  return EXIT_SUCCESS;
}

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 )

target_link_libraries(StructuredPointsToUnstructuredGrid ${VTK_LIBRARIES})

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

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