# StructuredPointsToUnstructuredGrid

vtk-examples/Cxx/StructuredPoints/StructuredPointsToUnstructuredGrid

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See (Java)

Question

### Code¶

StructuredPointsToUnstructuredGrid.cxx

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

int main(int, char*[])
{
// Create a structuredpoints
vtkNew<vtkStructuredPoints> structuredPoints;

// 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
vtkNew<vtkPoints> points;

// 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);
}

vtkNew<vtkUnstructuredGrid> ug;
ug->SetPoints(points);

vtkNew<vtkXMLUnstructuredGridWriter> writer;
writer->SetFileName("output.vtu");
writer->SetInputData(ug);
writer->Write();

return EXIT_SUCCESS;
}


### CMakeLists.txt¶

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(StructuredPointsToUnstructuredGrid)

find_package(VTK COMPONENTS
CommonCore
CommonDataModel
IOXML
)

if (NOT VTK_FOUND)
message(FATAL_ERROR "StructuredPointsToUnstructuredGrid: Unable to find the VTK build folder.")
endif()

# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
target_link_libraries(StructuredPointsToUnstructuredGrid PRIVATE ${VTK_LIBRARIES} ) # vtk_module_autoinit is needed vtk_module_autoinit( TARGETS StructuredPointsToUnstructuredGrid MODULES${VTK_LIBRARIES}
)


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.