# StructuredPointsToUnstructuredGrid

VTKExamples/Cxx/StructuredPoints/StructuredPointsToUnstructuredGrid

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### 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 3.3 FATAL_ERROR)

project(StructuredPointsToUnstructuredGrid)

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


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.