NOVCAGraph

VTKEx/Cxx/Graphs/NOVCAGraph

Description

  • This example shows how to construct a graph to visualize it in ParaView/VisIt using the VTK output file testVertex.vtu.

  • Contributed by Sanjaya Gajurel, Case Western Reserve University

Other languages

See (Python)

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

NOVCAGraph.cxx

#include <vtkCellArray.h>
#include <vtkPoints.h>
#include <vtkPolyLine.h>
#include <vtkTriangle.h>
#include <vtkXMLPolyDataWriter.h>
#include <vtkPolyData.h>
#include <vtkUnstructuredGrid.h>
#include <vtkXMLUnstructuredGridWriter.h>
#include <vtkSmartPointer.h>

int main ( int, char *[] )
{
  // Create 8 Vertices.
  vtkSmartPointer<vtkPoints> points =
    vtkSmartPointer<vtkPoints>::New();

  for ( unsigned int i = 0; i < 2; ++i )
     for ( unsigned int j = 0; j < 4; ++j )
          points->InsertNextPoint( i, j, 0);

   //Create Edges
    vtkSmartPointer<vtkPolyLine> line =
    vtkSmartPointer<vtkPolyLine>::New();
    line->GetPointIds()->SetNumberOfIds(8);
  for ( unsigned int i = 0; i < 8; ++i )
      line->GetPointIds()->SetId(i,i);

   vtkSmartPointer<vtkCellArray> cellArray =
    vtkSmartPointer<vtkCellArray>::New();
   cellArray->InsertNextCell(line);

  // Create a Graph with Vertices and Edges.
  vtkSmartPointer<vtkUnstructuredGrid> grid =
    vtkSmartPointer<vtkUnstructuredGrid>::New();
  grid->SetPoints(points);
  grid->SetCells(VTK_POLY_LINE,cellArray);

  // Write the file
  vtkSmartPointer<vtkXMLUnstructuredGridWriter> writer =
    vtkSmartPointer<vtkXMLUnstructuredGridWriter>::New();
  writer->SetFileName("testVertex.vtu");
  writer->SetInputData(grid);
  writer->Write();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(NOVCAGraph)

find_package(VTK COMPONENTS 
  vtkvtkCommonCore
  vtkvtkCommonDataModel
  vtkvtkIOXML QUIET)
if (NOT VTK_FOUND)
  message("Skipping NOVCAGraph: ${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(NOVCAGraph MACOSX_BUNDLE NOVCAGraph.cxx )
  target_link_libraries(NOVCAGraph PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(NOVCAGraph MACOSX_BUNDLE NOVCAGraph.cxx )
  target_link_libraries(NOVCAGraph PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS NOVCAGraph
    MODULES ${VTK_LIBRARIES}
    )
endif ()

Download and Build NOVCAGraph

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

cd NOVCAGraph/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:

./NOVCAGraph

WINDOWS USERS

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