EllipticalCylinderDemo
vtk-examples/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.
Other languages
See (Python)
Question
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Code¶
EllipticalCylinderDemo.cxx
#include <vtkActor.h>
#include <vtkArrowSource.h>
#include <vtkCamera.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkLinearExtrusionFilter.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPoints.h>
#include <vtkPolyDataMapper.h>
#include <vtkPolyLine.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.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]);
}
vtkNew<vtkNamedColors> colors;
double angle = 0;
double r1, r2;
double centerX, centerY;
r1 = 50;
r2 = 30;
centerX = 10.0;
centerY = 5.0;
vtkNew<vtkPoints> points;
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;
}
vtkNew<vtkPolyLine> line;
line->GetPointIds()->SetNumberOfIds(id);
for (unsigned int i = 0; i < static_cast<unsigned int>(id); ++i)
{
line->GetPointIds()->SetId(i, i);
}
vtkNew<vtkCellArray> lines;
lines->InsertNextCell(line);
vtkNew<vtkPolyData> polyData;
polyData->SetPoints(points);
polyData->SetLines(lines);
vtkNew<vtkLinearExtrusionFilter> extrude;
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);
vtkNew<vtkMatrix4x4> matrix;
// 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
vtkNew<vtkTransform> transform;
transform->Translate(startPoint);
transform->Concatenate(matrix);
transform->Scale(length, length, length);
vtkNew<vtkArrowSource> arrowSource;
arrowSource->SetTipResolution(31);
arrowSource->SetShaftResolution(21);
// Transform the polydata
vtkNew<vtkTransformPolyDataFilter> transformPD;
transformPD->SetTransform(transform);
transformPD->SetInputConnection(arrowSource->GetOutputPort());
// Create a mapper and actor for the arrow
vtkNew<vtkPolyDataMapper> arrowMapper;
arrowMapper->SetInputConnection(transformPD->GetOutputPort());
vtkNew<vtkActor> arrowActor;
arrowActor->SetMapper(arrowMapper);
arrowActor->GetProperty()->SetColor(colors->GetColor3d("Tomato").GetData());
vtkNew<vtkTubeFilter> tubes;
tubes->SetInputData(polyData);
tubes->SetRadius(2.0);
tubes->SetNumberOfSides(21);
vtkNew<vtkPolyDataMapper> lineMapper;
lineMapper->SetInputConnection(tubes->GetOutputPort());
vtkNew<vtkActor> lineActor;
lineActor->SetMapper(lineMapper);
lineActor->GetProperty()->SetColor(colors->GetColor3d("Peacock").GetData());
vtkNew<vtkPolyDataMapper> mapper;
mapper->SetInputConnection(extrude->GetOutputPort());
vtkNew<vtkActor> actor;
actor->SetMapper(mapper);
actor->GetProperty()->SetColor(colors->GetColor3d("Banana").GetData());
actor->GetProperty()->SetOpacity(.7);
vtkNew<vtkRenderer> ren;
ren->SetBackground(colors->GetColor3d("SlateGray").GetData());
ren->AddActor(actor);
ren->AddActor(lineActor);
ren->AddActor(arrowActor);
vtkNew<vtkRenderWindow> renWin;
renWin->SetWindowName("EllipticalCylinderDemo");
renWin->AddRenderer(ren);
renWin->SetSize(600, 600);
vtkNew<vtkRenderWindowInteractor> iren;
iren->SetRenderWindow(renWin);
vtkNew<vtkInteractorStyleTrackballCamera> style;
iren->SetInteractorStyle(style);
vtkNew<vtkCamera> camera;
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 3.3 FATAL_ERROR)
project(EllipticalCylinderDemo)
find_package(VTK COMPONENTS
vtkCommonColor
vtkCommonCore
vtkCommonDataModel
vtkCommonTransforms
vtkFiltersCore
vtkFiltersGeneral
vtkFiltersModeling
vtkFiltersSources
vtkInteractionStyle
vtkRenderingContextOpenGL2
vtkRenderingCore
vtkRenderingFreeType
vtkRenderingGL2PSOpenGL2
vtkRenderingOpenGL2
QUIET
)
if (NOT VTK_FOUND)
message("Skipping EllipticalCylinderDemo: ${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(EllipticalCylinderDemo MACOSX_BUNDLE EllipticalCylinderDemo.cxx )
target_link_libraries(EllipticalCylinderDemo PRIVATE ${VTK_LIBRARIES})
else ()
# include all components
add_executable(EllipticalCylinderDemo MACOSX_BUNDLE EllipticalCylinderDemo.cxx )
target_link_libraries(EllipticalCylinderDemo PRIVATE ${VTK_LIBRARIES})
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS EllipticalCylinderDemo
MODULES ${VTK_LIBRARIES}
)
endif ()
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.