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UGrid

vtk-examples/Cxx/UnstructuredGrid/UGrid


Description

Creation of an unstructured grid.

Other languages

See (Python)

Question

If you have a question about this example, please use the VTK Discourse Forum

Code

UGrid.cxx

#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkCellType.h>
#include <vtkDataSetMapper.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>

int main(int, char*[])
{
  int i;
  static double x[27][3] = {
      {0, 0, 0}, {1, 0, 0}, {2, 0, 0}, {0, 1, 0}, {1, 1, 0}, {2, 1, 0},
      {0, 0, 1}, {1, 0, 1}, {2, 0, 1}, {0, 1, 1}, {1, 1, 1}, {2, 1, 1},
      {0, 1, 2}, {1, 1, 2}, {2, 1, 2}, {0, 1, 3}, {1, 1, 3}, {2, 1, 3},
      {0, 1, 4}, {1, 1, 4}, {2, 1, 4}, {0, 1, 5}, {1, 1, 5}, {2, 1, 5},
      {0, 1, 6}, {1, 1, 6}, {2, 1, 6}};
  static vtkIdType pts[12][8] = {
      {0, 1, 4, 3, 6, 7, 10, 9},      {1, 2, 5, 4, 7, 8, 11, 10},
      {6, 10, 9, 12, 0, 0, 0, 0},     {8, 11, 10, 14, 0, 0, 0, 0},
      {16, 17, 14, 13, 12, 15, 0, 0}, {18, 15, 19, 16, 20, 17, 0, 0},
      {22, 23, 20, 19, 0, 0, 0, 0},   {21, 22, 18, 0, 0, 0, 0, 0},
      {22, 19, 18, 0, 0, 0, 0, 0},    {23, 26, 0, 0, 0, 0, 0, 0},
      {21, 24, 0, 0, 0, 0, 0, 0},     {25, 0, 0, 0, 0, 0, 0, 0}};

  vtkNew<vtkNamedColors> colors;

  vtkNew<vtkRenderer> renderer;

  vtkNew<vtkRenderWindow> renWin;
  renWin->AddRenderer(renderer);
  vtkNew<vtkRenderWindowInteractor> iren;
  iren->SetRenderWindow(renWin);

  vtkNew<vtkPoints> points;
  for (i = 0; i < 27; i++) points->InsertPoint(i, x[i]);

  vtkNew<vtkUnstructuredGrid> ugrid;
  ugrid->Allocate(100);
  ugrid->InsertNextCell(VTK_HEXAHEDRON, 8, pts[0]);
  ugrid->InsertNextCell(VTK_HEXAHEDRON, 8, pts[1]);
  ugrid->InsertNextCell(VTK_TETRA, 4, pts[2]);
  ugrid->InsertNextCell(VTK_TETRA, 4, pts[3]);
  ugrid->InsertNextCell(VTK_POLYGON, 6, pts[4]);
  ugrid->InsertNextCell(VTK_TRIANGLE_STRIP, 6, pts[5]);
  ugrid->InsertNextCell(VTK_QUAD, 4, pts[6]);
  ugrid->InsertNextCell(VTK_TRIANGLE, 3, pts[7]);
  ugrid->InsertNextCell(VTK_TRIANGLE, 3, pts[8]);
  ugrid->InsertNextCell(VTK_LINE, 2, pts[9]);
  ugrid->InsertNextCell(VTK_LINE, 2, pts[10]);
  ugrid->InsertNextCell(VTK_VERTEX, 1, pts[11]);

  ugrid->SetPoints(points);

  vtkNew<vtkDataSetMapper> ugridMapper;
  ugridMapper->SetInputData(ugrid);

  vtkNew<vtkActor> ugridActor;
  ugridActor->SetMapper(ugridMapper);
  ugridActor->GetProperty()->SetColor(colors->GetColor3d("Peacock").GetData());
  ugridActor->GetProperty()->EdgeVisibilityOn();

  renderer->AddActor(ugridActor);
  renderer->SetBackground(colors->GetColor3d("Beige").GetData());

  renderer->ResetCamera();
  renderer->GetActiveCamera()->Elevation(60.0);
  renderer->GetActiveCamera()->Azimuth(30.0);
  renderer->GetActiveCamera()->Dolly(1.2);

  renWin->SetSize(640, 480);
  renWin->SetWindowName("UGrid)");

  // interact with data
  renWin->Render();

  iren->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(UGrid)

find_package(VTK COMPONENTS 
  vtkCommonColor
  vtkCommonCore
  vtkCommonDataModel
  vtkInteractionStyle
  vtkRenderingContextOpenGL2
  vtkRenderingCore
  vtkRenderingFreeType
  vtkRenderingGL2PSOpenGL2
  vtkRenderingOpenGL2
  QUIET
)

if (NOT VTK_FOUND)
  message("Skipping UGrid: ${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(UGrid MACOSX_BUNDLE UGrid.cxx )
  target_link_libraries(UGrid PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(UGrid MACOSX_BUNDLE UGrid.cxx )
  target_link_libraries(UGrid PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS UGrid
    MODULES ${VTK_LIBRARIES}
    )
endif ()

Download and Build UGrid

Click here to download UGrid and its CMakeLists.txt file. Once the tarball UGrid.tar has been downloaded and extracted,

cd UGrid/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:

./UGrid

WINDOWS USERS

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