IsosurfaceSampling
VTKExamples/Cxx/Visualization/IsosurfaceSampling
Description¶
This example illustrates how to create an isosurface and create point data on that isosurface that is sampled from another dataset. This example creates an isosurface of a sphere and then uses the vtkProbeFilter to compute point data from a sampled cylinder. '''Note''', that all point data is sampled, even the normals. This example restores the original isosurface normals after the probe. The example has one optional command line argument that controls the sample resolution of the sphere and cylinder. The default is 50.
Code¶
IsosurfaceSampling.cxx
#include <vtkVersion.h> #include <vtkSmartPointer.h> #include <vtkSampleFunction.h> #include <vtkSphere.h> #include <vtkCylinder.h> #include <vtkMarchingCubes.h> #include <vtkProbeFilter.h> #include <vtkImageData.h> #include <vtkPointData.h> #include <vtkPolyDataMapper.h> #include <vtkProperty.h> #include <vtkActor.h> #include <vtkRenderWindow.h> #include <vtkRenderer.h> #include <vtkRenderWindowInteractor.h> #include <vtkUnsignedCharArray.h> int main(int argc, char *argv[]) { int resolution = 50; if (argc > 1) { resolution = atoi(argv[1]); } // Create a sampled sphere vtkSmartPointer<vtkSphere> implicitSphere = vtkSmartPointer<vtkSphere>::New(); double radius = 1.0; implicitSphere->SetRadius(radius); vtkSmartPointer<vtkSampleFunction> sampledSphere = vtkSmartPointer<vtkSampleFunction>::New(); sampledSphere->SetSampleDimensions(resolution, resolution, resolution); double xMin = -radius * 2.0; double xMax = radius * 2.0; sampledSphere->SetModelBounds(xMin, xMax, xMin, xMax, xMin, xMax); sampledSphere->SetImplicitFunction(implicitSphere); vtkSmartPointer<vtkMarchingCubes> isoSphere = vtkSmartPointer<vtkMarchingCubes>:: New(); isoSphere->SetValue(0,1.0); isoSphere->SetInputConnection(sampledSphere->GetOutputPort()); // Create a sampled cylinder vtkSmartPointer<vtkCylinder> implicitCylinder = vtkSmartPointer<vtkCylinder>::New(); implicitCylinder->SetRadius(radius/2.0); vtkSmartPointer<vtkSampleFunction> sampledCylinder = vtkSmartPointer<vtkSampleFunction>::New(); sampledCylinder->SetSampleDimensions(resolution, resolution, resolution); sampledCylinder->SetModelBounds(xMin, xMax, xMin, xMax, xMin, xMax); sampledCylinder->SetImplicitFunction(implicitCylinder); // Probe cylinder with the sphere isosurface vtkSmartPointer<vtkProbeFilter> probeCylinder = vtkSmartPointer<vtkProbeFilter>::New(); probeCylinder->SetInputConnection(0, isoSphere->GetOutputPort()); probeCylinder->SetInputConnection(1, sampledCylinder->GetOutputPort()); probeCylinder->Update(); // Restore the original normals probeCylinder->GetOutput()->GetPointData()->SetNormals( isoSphere->GetOutput()->GetPointData()->GetNormals()); std::cout << "Scalar range: " << probeCylinder->GetOutput()->GetScalarRange()[0] << ", " << probeCylinder->GetOutput()->GetScalarRange()[1] << std::endl; // Create a mapper and actor vtkSmartPointer<vtkPolyDataMapper> mapSphere = vtkSmartPointer<vtkPolyDataMapper>::New(); mapSphere->SetInputConnection(probeCylinder->GetOutputPort()); mapSphere->SetScalarRange(probeCylinder->GetOutput()->GetScalarRange()); vtkSmartPointer<vtkActor> sphere = vtkSmartPointer<vtkActor>::New(); sphere->SetMapper(mapSphere); // Visualize 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(sphere); renderer->SetBackground(1,1,1); // Background color white renderWindow->Render(); renderWindowInteractor->Start(); return EXIT_SUCCESS; }
CMakeLists.txt¶
cmake_minimum_required(VERSION 2.8) PROJECT(IsosurfaceSampling) find_package(VTK REQUIRED) include(${VTK_USE_FILE}) add_executable(IsosurfaceSampling MACOSX_BUNDLE IsosurfaceSampling.cxx) target_link_libraries(IsosurfaceSampling ${VTK_LIBRARIES})
Download and Build IsosurfaceSampling¶
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 IsosurfaceSampling and its CMakeLists.txt file. Once the tarball IsosurfaceSampling.tar has been downloaded and extracted,
cd IsosurfaceSampling/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:
./IsosurfaceSampling
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.