Skip to content

NOVCAGraph

vtk-examples/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 question about this example, please use the VTK Discourse Forum

Code

NOVCAGraph.cxx

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

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

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

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

  vtkNew<vtkCellArray> cellArray;
  cellArray->InsertNextCell(line);

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

  // Write the file
  vtkNew<vtkXMLUnstructuredGridWriter> writer;
  writer->SetFileName("vertex.vtu");
  writer->SetInputData(grid);
  writer->Write();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(NOVCAGraph)

find_package(VTK COMPONENTS 
  CommonCore
  CommonDataModel
  IOXML
  QUIET
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "NOVCAGraph: 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(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}
)

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.