# Polyhedron

vtk-examples/Cxx/GeometricObjects/Polyhedron

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See (Python)

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### Code¶

Polyhedron.cxx

#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkDataSetMapper.h>
#include <vtkIdList.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPoints.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkUnstructuredGrid.h>
#include <vtkXMLUnstructuredGridWriter.h>

int main(int, char*[])
{
vtkNew<vtkNamedColors> colors;

// Create the polyhedron, a cube.
vtkIdType pointIds[8] = {0, 1, 2, 3, 4, 5, 6, 7};

vtkNew<vtkPoints> points;
points->InsertNextPoint(-1.0, -1.0, -1.0);
points->InsertNextPoint(1.0, -1.0, -1.0);
points->InsertNextPoint(1.0, 1.0, -1.0);
points->InsertNextPoint(-1.0, 1.0, -1.0);
points->InsertNextPoint(-1.0, -1.0, 1.0);
points->InsertNextPoint(1.0, -1.0, 1.0);
points->InsertNextPoint(1.0, 1.0, 1.0);
points->InsertNextPoint(-1.0, 1.0, 1.0);

vtkNew<vtkIdList> faces;
vtkIdType face0[4] = {0, 3, 2, 1};
vtkIdType face1[4] = {0, 4, 7, 3};
vtkIdType face2[4] = {4, 5, 6, 7};
vtkIdType face3[4] = {5, 1, 2, 6};
vtkIdType face4[4] = {0, 1, 5, 4};
vtkIdType face5[4] = {2, 3, 7, 6};

auto addFace = [&](const vtkIdType face[4]) {
faces->InsertNextId(4);
for (int i = 0; i < 4; ++i)
{
faces->InsertNextId(face[i]);
}
};

vtkNew<vtkUnstructuredGrid> ugrid;
ugrid->SetPoints(points);
ugrid->InsertNextCell(VTK_POLYHEDRON, 8, pointIds, 6, faces->GetPointer(0));

// Here we write out the cube.
vtkNew<vtkXMLUnstructuredGridWriter> writer;
writer->SetInputData(ugrid);
writer->SetFileName("polyhedron.vtu");
writer->SetDataModeToAscii();
writer->Update();

// Create a mapper and actor
vtkNew<vtkDataSetMapper> mapper;
mapper->SetInputData(ugrid);

vtkNew<vtkActor> actor;
actor->SetMapper(mapper);
actor->GetProperty()->SetColor(colors->GetColor3d("Silver").GetData());

// Visualize.
vtkNew<vtkRenderer> renderer;
vtkNew<vtkRenderWindow> renderWindow;
renderWindow->SetWindowName("Polyhedron");
vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
renderWindowInteractor->SetRenderWindow(renderWindow);

renderer->SetBackground(colors->GetColor3d("Salmon").GetData());
renderer->ResetCamera();
renderer->GetActiveCamera()->Azimuth(30);
renderer->GetActiveCamera()->Elevation(30);
renderWindow->Render();
renderWindowInteractor->Start();

return EXIT_SUCCESS;
}


### CMakeLists.txt¶

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(Polyhedron)

find_package(VTK COMPONENTS
CommonColor
CommonCore
CommonDataModel
IOXML
InteractionStyle
RenderingContextOpenGL2
RenderingCore
RenderingFreeType
RenderingGL2PSOpenGL2
RenderingOpenGL2
)

if (NOT VTK_FOUND)
message(FATAL_ERROR "Polyhedron: 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(Polyhedron PRIVATE ${VTK_LIBRARIES} ) # vtk_module_autoinit is needed vtk_module_autoinit( TARGETS Polyhedron MODULES${VTK_LIBRARIES}
)


cd Polyhedron/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:

./Polyhedron


WINDOWS USERS

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