ReadUnstructuredGrid

VTKEx/Cxx/IO/ReadUnstructuredGrid

Description

This example demonstrates how to read an unstructured grid (VTU) file. The front facing faces are colored white, while the back facing faces are colored red.

An example data file (.vtu) for testing can be found in VTKExamples/src/TestingData/tetra.vtu.

Other languages

See (Python), (CSharp)

Question

If you have a simple question about this example contact us at VTKExProject If your question is more complex and may require extended discussion, please use the VTK Discourse Forum

Code

ReadUnstructuredGrid.cxx

#include <vtkSmartPointer.h>
#include <vtkXMLUnstructuredGridReader.h>

#include <vtkDataSetMapper.h>
#include <vtkActor.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkProperty.h>
#include <vtkNamedColors.h>

int main ( int argc, char *argv[] )
{
  //parse command line arguments
  if(argc < 2)
  {
    std::cerr << "Usage: " << argv[0]
              << " Filename(.vtu)" << std::endl;
    return EXIT_FAILURE;
  }

  std::string filename = argv[1];

  //read all the data from the file
  vtkSmartPointer<vtkXMLUnstructuredGridReader> reader =
    vtkSmartPointer<vtkXMLUnstructuredGridReader>::New();
  reader->SetFileName(filename.c_str());
  reader->Update();

  vtkSmartPointer<vtkNamedColors> colors =
    vtkSmartPointer<vtkNamedColors>::New();

  //Create a mapper and actor
  vtkSmartPointer<vtkDataSetMapper> mapper =
    vtkSmartPointer<vtkDataSetMapper>::New();
  mapper->SetInputConnection(reader->GetOutputPort());
  mapper->ScalarVisibilityOff();

  vtkSmartPointer<vtkActor> actor =
    vtkSmartPointer<vtkActor>::New();
  actor->SetMapper(mapper);
  actor->GetProperty()->EdgeVisibilityOn();
  actor->GetProperty()->SetLineWidth(2.0);

  vtkSmartPointer<vtkProperty> backFace =
    vtkSmartPointer<vtkProperty>::New();
  backFace->SetColor(colors->GetColor3d("tomato").GetData());
  actor->SetBackfaceProperty(backFace);

  //Create a renderer, render window, and interactor
  vtkSmartPointer<vtkRenderer> renderer =
    vtkSmartPointer<vtkRenderer>::New();
  vtkSmartPointer<vtkRenderWindow> renderWindow =
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);
  vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  renderWindowInteractor->SetRenderWindow(renderWindow);

  //Add the actor to the scene
  renderer->AddActor(actor);
  renderer->SetBackground(colors->GetColor3d("Wheat").GetData());

  //Render and interact
  renderWindow->SetSize(640, 480);

  renderWindow->Render();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(ReadUnstructuredGrid)

find_package(VTK COMPONENTS 
  vtkvtkCommonColor
  vtkvtkCommonCore
  vtkvtkIOXML
  vtkvtkInteractionStyle
  vtkvtkRenderingContextOpenGL2
  vtkvtkRenderingCore
  vtkvtkRenderingFreeType
  vtkvtkRenderingGL2PSOpenGL2
  vtkvtkRenderingOpenGL2 QUIET)
if (NOT VTK_FOUND)
  message("Skipping ReadUnstructuredGrid: ${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(ReadUnstructuredGrid MACOSX_BUNDLE ReadUnstructuredGrid.cxx )
  target_link_libraries(ReadUnstructuredGrid PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(ReadUnstructuredGrid MACOSX_BUNDLE ReadUnstructuredGrid.cxx )
  target_link_libraries(ReadUnstructuredGrid PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS ReadUnstructuredGrid
    MODULES ${VTK_LIBRARIES}
    )
endif ()

Download and Build ReadUnstructuredGrid

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

cd ReadUnstructuredGrid/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:

./ReadUnstructuredGrid

WINDOWS USERS

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