EllipticalCylinderDemo

VTKExamples/Cxx/GeometricObjects/EllipticalCylinderDemo


Description

The example shows the vtkPolyLine that forms the base of the elliptical cylinder and an oriented arrow that represents the vector that vtkLinearExtrusionFilter uses to create the cylinder. The example takes an optional triple that defines the vector for the filter. The length of the vector is the height of the cylinder.

Code

EllipticalCylinderDemo.cxx

#include <vtkActor.h>
#include <vtkArrowSource.h>
#include <vtkCamera.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkLinearExtrusionFilter.h>
#include <vtkNamedColors.h>
#include <vtkPoints.h>
#include <vtkPolyDataMapper.h>
#include <vtkPolyLine.h>
#include <vtkProperty.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkSmartPointer.h>
#include <vtkTransform.h>
#include <vtkTransformPolyDataFilter.h>
#include <vtkTubeFilter.h>

int main(int argc, char *argv[])
{
  double nx = 0.0;
  double ny = 0.0;
  double nz = 100.0;

  if (argc > 3)
  {
    nx = atof(argv[1]);
    ny = atof(argv[2]);
    nz = atof(argv[3]);
  }
  vtkSmartPointer<vtkNamedColors> colors =
    vtkSmartPointer<vtkNamedColors>::New();

  double angle = 0;
  double r1, r2;
  double centerX, centerY;
  r1 = 50;
  r2 = 30;
  centerX = 10.0;
  centerY = 5.0;

  vtkSmartPointer<vtkPoints> points =
    vtkSmartPointer<vtkPoints>::New();
  int id = 0;
  while (angle <= 2.0 * vtkMath::Pi() + (vtkMath::Pi() / 60.0))
  {
    points->InsertNextPoint(r1 * cos(angle) + centerX,
                            r2 * sin(angle) + centerY,
                            0.0);
    angle = angle + (vtkMath::Pi() / 60.0);
    ++id;
  }

  vtkSmartPointer<vtkPolyLine> line =
    vtkSmartPointer<vtkPolyLine>::New();
  line->GetPointIds()->SetNumberOfIds(id);
  for(unsigned int i = 0; i < static_cast<unsigned int>(id); ++i)
  {
    line->GetPointIds()->SetId(i,i);
  }

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

  vtkSmartPointer<vtkPolyData> polyData =
    vtkSmartPointer<vtkPolyData>::New();
  polyData->SetPoints(points);
  polyData->SetLines(lines);

  vtkSmartPointer<vtkLinearExtrusionFilter> extrude =
    vtkSmartPointer<vtkLinearExtrusionFilter>::New();
  extrude->SetInputData(polyData);
  extrude->SetExtrusionTypeToNormalExtrusion();
  extrude->SetVector(nx, ny, nz);
  extrude->Update();

  // Create an oriented arrow
  double startPoint[3], endPoint[3];
  startPoint[0] = centerX;
  startPoint[1] = centerY;
  startPoint[2] = 0.0;
  endPoint[0] = startPoint[0] + extrude->GetVector()[0];
  endPoint[1] = startPoint[1] + extrude->GetVector()[1];
  endPoint[2] = startPoint[2] + extrude->GetVector()[2];

  // Compute a basis
  double normalizedX[3];
  double normalizedY[3];
  double normalizedZ[3];

  // The X axis is a vector from start to end
  vtkMath::Subtract(endPoint, startPoint, normalizedX);
  double length = vtkMath::Norm(normalizedX);
  vtkMath::Normalize(normalizedX);

  // The Z axis is an arbitrary vector cross X
  double arbitrary[3];
  arbitrary[0] = vtkMath::Random(-10,10);
  arbitrary[1] = vtkMath::Random(-10,10);
  arbitrary[2] = vtkMath::Random(-10,10);
  vtkMath::Cross(normalizedX, arbitrary, normalizedZ);
  vtkMath::Normalize(normalizedZ);

  // The Y axis is Z cross X
  vtkMath::Cross(normalizedZ, normalizedX, normalizedY);
  vtkSmartPointer<vtkMatrix4x4> matrix =
    vtkSmartPointer<vtkMatrix4x4>::New();

  // Create the direction cosine matrix
  matrix->Identity();
  for (unsigned int i = 0; i < 3; i++)
  {
    matrix->SetElement(i, 0, normalizedX[i]);
    matrix->SetElement(i, 1, normalizedY[i]);
    matrix->SetElement(i, 2, normalizedZ[i]);
  }

  // Apply the transforms
  vtkSmartPointer<vtkTransform> transform =
    vtkSmartPointer<vtkTransform>::New();
  transform->Translate(startPoint);
  transform->Concatenate(matrix);
  transform->Scale(length, length, length);

  vtkSmartPointer<vtkArrowSource> arrowSource =
    vtkSmartPointer<vtkArrowSource>::New();
  arrowSource->SetTipResolution(31);
  arrowSource->SetShaftResolution(21);

  // Transform the polydata
  vtkSmartPointer<vtkTransformPolyDataFilter> transformPD =
    vtkSmartPointer<vtkTransformPolyDataFilter>::New();
  transformPD->SetTransform(transform);
  transformPD->SetInputConnection(arrowSource->GetOutputPort());

  //Create a mapper and actor for the arrow
  vtkSmartPointer<vtkPolyDataMapper> arrowMapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
  arrowMapper->SetInputConnection(transformPD->GetOutputPort());

  vtkSmartPointer<vtkActor> arrowActor =
    vtkSmartPointer<vtkActor>::New();
  arrowActor->SetMapper(arrowMapper);
  arrowActor->GetProperty()->SetColor(colors->GetColor3d("Tomato").GetData());

  vtkSmartPointer<vtkTubeFilter> tubes =
    vtkSmartPointer<vtkTubeFilter>::New();
  tubes->SetInputData(polyData);
  tubes->SetRadius(2.0);
  tubes->SetNumberOfSides(21);

  vtkSmartPointer<vtkPolyDataMapper> lineMapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
  lineMapper->SetInputConnection(tubes->GetOutputPort());

  vtkSmartPointer<vtkActor> lineActor =
    vtkSmartPointer<vtkActor>::New();
  lineActor->SetMapper(lineMapper);
  lineActor->GetProperty()->SetColor(colors->GetColor3d("Peacock").GetData());

  vtkSmartPointer<vtkPolyDataMapper> mapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
  mapper->SetInputConnection(extrude->GetOutputPort());

  vtkSmartPointer<vtkActor> actor =
    vtkSmartPointer<vtkActor>::New();
  actor->SetMapper(mapper);
  actor->GetProperty()->SetColor(colors->GetColor3d("Banana").GetData());
  actor->GetProperty()->SetOpacity(.7);

  vtkSmartPointer<vtkRenderer> ren =
    vtkSmartPointer<vtkRenderer>::New();
  ren->SetBackground(colors->GetColor3d("SlateGray").GetData());
  ren->AddActor(actor);
  ren->AddActor(lineActor);
  ren->AddActor(arrowActor);

  vtkSmartPointer<vtkRenderWindow> renWin =
    vtkSmartPointer<vtkRenderWindow>::New();
  renWin->SetWindowName("Elliptical Cylinder Demo");
  renWin->AddRenderer(ren);
  renWin->SetSize(600, 600);

  vtkSmartPointer<vtkRenderWindowInteractor> iren =
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  iren->SetRenderWindow(renWin);

  vtkSmartPointer<vtkInteractorStyleTrackballCamera> style =
    vtkSmartPointer<vtkInteractorStyleTrackballCamera>::New();
  iren->SetInteractorStyle(style);

  vtkSmartPointer<vtkCamera> camera =
    vtkSmartPointer<vtkCamera>::New();
  camera->SetPosition (0, 1, 0);
  camera->SetFocalPoint (0, 0, 0);
  camera->SetViewUp (0, 0, 1);
  camera->Azimuth(30);
  camera->Elevation(30);


  ren->SetActiveCamera(camera);
  ren->ResetCamera();
  ren->ResetCameraClippingRange();

  renWin->Render();
  iren->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 2.8)

PROJECT(EllipticalCylinderDemo)

find_package(VTK REQUIRED)
include(${VTK_USE_FILE})

add_executable(EllipticalCylinderDemo MACOSX_BUNDLE EllipticalCylinderDemo.cxx )

target_link_libraries(EllipticalCylinderDemo ${VTK_LIBRARIES})

Download and Build EllipticalCylinderDemo

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

cd EllipticalCylinderDemo/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:

./EllipticalCylinderDemo

WINDOWS USERS

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