ClipUnstructuredGridWithPlane2
vtk-examples/Cxx/UnstructuredGrid/ClipUnstructuredGridWithPlane2
Description¶
The example uses vtkClipDataSet to clip a vtkUnstructuredGrid. The resulting output and clipped output are presented in yellow and red respectively. To illustrate the clipped interfaces, the example uses a vtkTransform to rotate each output about their centers.
Note that this clipping filter does not retain the original cells if they are not clipped.
After exiting, the example reports the number of each cell type for each output:
The inside dataset contains a
[vtkUnstructuredGrid](https://www.vtk.org/doc/nightly/html/classvtkUnstructuredGrid.html#details) that has 110148 cells
Cell type [vtkTetra](https://www.vtk.org/doc/nightly/html/classvtkTetra.html#details) occurs 106998 times.
Cell type [vtkWedge](https://www.vtk.org/doc/nightly/html/classvtkWedge.html#details) occurs 3150 times.
The clipped dataset contains a
[vtkUnstructuredGrid](https://www.vtk.org/doc/nightly/html/classvtkUnstructuredGrid.html#details) that has 111824 cells
Cell type [vtkTetra](https://www.vtk.org/doc/nightly/html/classvtkTetra.html#details) occurs 107420 times.
Cell type [vtkWedge](https://www.vtk.org/doc/nightly/html/classvtkWedge.html#details) occurs 4404 times.
Compare these results with ClipUnstructuredGridWithPlane (C++) ClipUnstructuredGridWithPlane (Python). Notice that in this example, the original vtkHexahedron in the unclipped regions are converted to vtkTetra. Also, the resulting vtkUnstructuredGrid's have more than 4 times the number of cells.
usage
ClipUnstructuredGridWithPlane2 treemesh.vtk
thanks
Thanks to Bane Sullivan for sharing the treemesh.vtk unstructured grid dataset.
Other languages
See (Python)
Question
If you have a question about this example, please use the VTK Discourse Forum
Code¶
ClipUnstructuredGridWithPlane2.cxx
#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkCellTypes.h>
#include <vtkClipDataSet.h>
#include <vtkDataSetMapper.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPlane.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkTransform.h>
#include <vtkUnstructuredGrid.h>
#include <vtkUnstructuredGridReader.h>
#include <iostream>
#include <string>
int main(int argc, char* argv[])
{
if (argc < 2)
{
std::cout << "Usage: " << argv[0] << " filename.vtk e.g. treemesh.vtk"
<< std::endl;
return EXIT_FAILURE;
}
// Create the reader for the data.
std::string filename = argv[1];
std::cout << "Loading " << filename.c_str() << std::endl;
vtkNew<vtkUnstructuredGridReader> reader;
reader->SetFileName(filename.c_str());
reader->Update();
double bounds[6];
reader->GetOutput()->GetBounds(bounds);
double center[3];
reader->GetOutput()->GetCenter(center);
vtkNew<vtkNamedColors> colors;
vtkNew<vtkRenderer> renderer;
renderer->SetBackground(colors->GetColor3d("Wheat").GetData());
renderer->UseHiddenLineRemovalOn();
vtkNew<vtkRenderWindow> renderWindow;
renderWindow->AddRenderer(renderer);
renderWindow->SetSize(640, 480);
vtkNew<vtkRenderWindowInteractor> interactor;
interactor->SetRenderWindow(renderWindow);
double xnorm[3] = {-1.0, -1.0, 1.0};
vtkNew<vtkPlane> clipPlane;
clipPlane->SetOrigin(reader->GetOutput()->GetCenter());
clipPlane->SetNormal(xnorm);
vtkNew<vtkClipDataSet> clipper;
clipper->SetClipFunction(clipPlane);
clipper->SetInputData(reader->GetOutput());
clipper->SetValue(0.0);
clipper->GenerateClippedOutputOn();
clipper->Update();
vtkNew<vtkDataSetMapper> insideMapper;
insideMapper->SetInputData(clipper->GetOutput());
insideMapper->ScalarVisibilityOff();
vtkNew<vtkActor> insideActor;
insideActor->SetMapper(insideMapper);
insideActor->GetProperty()->SetDiffuseColor(
colors->GetColor3d("banana").GetData());
insideActor->GetProperty()->SetAmbient(.3);
insideActor->GetProperty()->EdgeVisibilityOn();
vtkNew<vtkDataSetMapper> clippedMapper;
clippedMapper->SetInputData(clipper->GetClippedOutput());
clippedMapper->ScalarVisibilityOff();
vtkNew<vtkActor> clippedActor;
clippedActor->SetMapper(clippedMapper);
clippedActor->GetProperty()->SetDiffuseColor(
colors->GetColor3d("tomato").GetData());
insideActor->GetProperty()->SetAmbient(.3);
clippedActor->GetProperty()->EdgeVisibilityOn();
// Create transforms to make a better visualization
vtkNew<vtkTransform> insideTransform;
insideTransform->Translate(-(bounds[1] - bounds[0]) * .75, 0, 0);
insideTransform->Translate(center[0], center[1], center[2]);
insideTransform->RotateY(-120.0);
insideTransform->Translate(-center[0], -center[1], -center[2]);
insideActor->SetUserTransform(insideTransform);
vtkNew<vtkTransform> clippedTransform;
clippedTransform->Translate((bounds[1] - bounds[0]) * .75, 0, 0);
clippedTransform->Translate(center[0], center[1], center[2]);
clippedTransform->RotateY(60.0);
clippedTransform->Translate(-center[0], -center[1], -center[2]);
clippedActor->SetUserTransform(clippedTransform);
renderer->AddViewProp(clippedActor);
renderer->AddViewProp(insideActor);
renderer->ResetCamera();
renderer->GetActiveCamera()->Dolly(1.4);
renderer->ResetCameraClippingRange();
renderWindow->Render();
renderWindow->SetWindowName("ClipUnstructuredGridWithPlane2");
renderWindow->Render();
interactor->Start();
// Generate a report
vtkIdType numberOfCells = clipper->GetOutput()->GetNumberOfCells();
std::cout << "------------------------" << std::endl;
std::cout << "The inside dataset contains a " << std::endl
<< clipper->GetOutput()->GetClassName() << " that has "
<< numberOfCells << " cells" << std::endl;
typedef std::map<int, int> CellContainer;
CellContainer cellMap;
for (vtkIdType i = 0; i < numberOfCells; i++)
{
cellMap[clipper->GetOutput()->GetCellType(i)]++;
}
for (auto c : cellMap)
{
std::cout << "\tCell type " << vtkCellTypes::GetClassNameFromTypeId(c.first)
<< " occurs " << c.second << " times." << std::endl;
}
numberOfCells = clipper->GetClippedOutput()->GetNumberOfCells();
std::cout << "------------------------" << std::endl;
std::cout << "The clipped dataset contains a " << std::endl
<< clipper->GetClippedOutput()->GetClassName() << " that has "
<< numberOfCells << " cells" << std::endl;
typedef std::map<int, int> OutsideCellContainer;
CellContainer outsideCellMap;
for (vtkIdType i = 0; i < numberOfCells; i++)
{
outsideCellMap[clipper->GetClippedOutput()->GetCellType(i)]++;
}
for (auto c : outsideCellMap)
{
std::cout << "\tCell type " << vtkCellTypes::GetClassNameFromTypeId(c.first)
<< " occurs " << c.second << " times." << std::endl;
}
return EXIT_SUCCESS;
}
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
project(ClipUnstructuredGridWithPlane2)
find_package(VTK COMPONENTS
)
if (NOT VTK_FOUND)
message(FATAL_ERROR "ClipUnstructuredGridWithPlane2: 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(ClipUnstructuredGridWithPlane2 MACOSX_BUNDLE ClipUnstructuredGridWithPlane2.cxx )
target_link_libraries(ClipUnstructuredGridWithPlane2 PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS ClipUnstructuredGridWithPlane2
MODULES ${VTK_LIBRARIES}
)
Download and Build ClipUnstructuredGridWithPlane2¶
Click here to download ClipUnstructuredGridWithPlane2 and its CMakeLists.txt file. Once the tarball ClipUnstructuredGridWithPlane2.tar has been downloaded and extracted,
cd ClipUnstructuredGridWithPlane2/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:
./ClipUnstructuredGridWithPlane2
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.