DeleteCells
VTKExamples/Cxx/PolyData/DeleteCells
Description¶
This example demonstrates how to delete a cell from a vtkPolyData. This is a three-step process: first, build upward-links from points to cells; second, mark cells for deletion; third, delete the marked cells. The first step is necessary to create a data structure suitable for efficient delete operations. Creating this data structure is computationally expensive, so it is only carried out before operations that need it, e.g. those that require changes to the topology.
Code¶
DeleteCells.cxx
#include <vtkActor.h> #include <vtkCellArray.h> #include <vtkLine.h> #include <vtkPoints.h> #include <vtkPolyData.h> #include <vtkPolyDataMapper.h> #include <vtkRenderer.h> #include <vtkRenderWindow.h> #include <vtkRenderWindowInteractor.h> #include <vtkSmartPointer.h> int main(int, char *[]) { vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New(); points->InsertNextPoint(0,0,0); points->InsertNextPoint(1,0,0); points->InsertNextPoint(1,1,0); points->InsertNextPoint(0,1,0); vtkSmartPointer<vtkLine> line0 = vtkSmartPointer<vtkLine>::New(); line0->GetPointIds()->SetId(0, 0); line0->GetPointIds()->SetId(1, 1); vtkSmartPointer<vtkLine> line1 = vtkSmartPointer<vtkLine>::New(); line1->GetPointIds()->SetId(0, 1); line1->GetPointIds()->SetId(1, 2); vtkSmartPointer<vtkLine> line2 = vtkSmartPointer<vtkLine>::New(); line2->GetPointIds()->SetId(0, 2); line2->GetPointIds()->SetId(1, 3); vtkSmartPointer<vtkCellArray> lines = vtkSmartPointer<vtkCellArray>::New(); lines->InsertNextCell(line0); lines->InsertNextCell(line1); lines->InsertNextCell(line2); vtkSmartPointer<vtkPolyData> polydata = vtkSmartPointer<vtkPolyData>::New(); polydata->SetPoints(points); polydata->SetLines(lines); // Tell the polydata to build 'upward' links from points to cells. polydata->BuildLinks(); // Mark a cell as deleted. polydata->DeleteCell(1); // Remove the marked cell. polydata->RemoveDeletedCells(); // Visualize vtkSmartPointer<vtkPolyDataMapper> mapper = vtkSmartPointer<vtkPolyDataMapper>::New(); mapper->SetInputDataObject(polydata); vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New(); actor->SetMapper(mapper); vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New(); vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New(); renderWindow->AddRenderer(renderer); vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = vtkSmartPointer<vtkRenderWindowInteractor>::New(); renderWindowInteractor->SetRenderWindow(renderWindow); renderer->AddActor(actor); renderWindow->Render(); renderWindowInteractor->Start(); return EXIT_SUCCESS; }
CMakeLists.txt¶
cmake_minimum_required(VERSION 2.8) PROJECT(DeleteCells) find_package(VTK REQUIRED) include(${VTK_USE_FILE}) add_executable(DeleteCells MACOSX_BUNDLE DeleteCells.cxx) target_link_libraries(DeleteCells ${VTK_LIBRARIES})
Download and Build DeleteCells¶
Danger
The generation of tar files has not been ported to the new VTKExamples. Some tarballs may be missing or out-of-date.
Click here to download DeleteCells and its CMakeLists.txt file. Once the tarball DeleteCells.tar has been downloaded and extracted,
cd DeleteCells/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:
./DeleteCells
WINDOWS USERS PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.