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ReadUnstructuredGrid

vtk-examples/Cxx/IO/ReadUnstructuredGrid

Description

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

An example file to use is src/Testing/Data/tetra.vtu.

Other languages

See (Python), (CSharp)

Question

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

Code

ReadUnstructuredGrid.cxx

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

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

  std::string filename = argv[1];

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

  vtkNew<vtkNamedColors> colors;

  // Create a mapper and actor
  vtkNew<vtkDataSetMapper> mapper;
  mapper->SetInputConnection(reader->GetOutputPort());
  mapper->ScalarVisibilityOff();

  vtkNew<vtkActor> actor;
  actor->SetMapper(mapper);
  actor->GetProperty()->EdgeVisibilityOn();
  actor->GetProperty()->SetLineWidth(2.0);
  actor->GetProperty()->SetColor(colors->GetColor3d("MistyRose").GetData());

  vtkNew<vtkProperty> backFace;
  backFace->SetColor(colors->GetColor3d("Tomato").GetData());
  actor->SetBackfaceProperty(backFace);

  // Create a renderer, render window, and interactor
  vtkNew<vtkRenderer> renderer;
  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->AddRenderer(renderer);
  vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
  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 3.12 FATAL_ERROR)

project(ReadUnstructuredGrid)

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

if (NOT VTK_FOUND)
  message(FATAL_ERROR "ReadUnstructuredGrid: 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.")
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}
)

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.