ImplicitSphere1

VTKExamples/Cxx/ImplicitFunctions/ImplicitSphere1


Shows how to create a surface representing a sphere by creating an implicit sphere, sampling the implicit function, and finally contouring the sampled data to produce the surface.

Question

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Code

ImplicitSphere1.cxx

#include <vtkSphere.h>
#include <vtkBox.h>
#include <vtkImplicitBoolean.h>
#include <vtkSampleFunction.h>
#include <vtkContourFilter.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkNamedColors.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkCamera.h>
#include <vtkProperty.h>
#include <vtkColor.h>

#include <cstdlib>

int main(int argc, char* argv[])
{
  // Define colors
  auto colors =
    vtkSmartPointer<vtkNamedColors>::New();
  vtkColor3d actorColor = colors->GetColor3d("AliceBlue");
  vtkColor3d  EdgeColour = colors->GetColor3d("SteelBlue");
  vtkColor3d BackgroundColour = colors->GetColor3d("Silver");

  // create a sphere
  auto sphere =
    vtkSmartPointer<vtkSphere>::New();
  sphere->SetCenter(0.0, 0.0, 0.0);
  sphere->SetRadius(0.5);

  /* The sample function generates a distance function from the implicit
     function.This is then contoured to get a polygonal surface.*/
  auto sample =
    vtkSmartPointer<vtkSampleFunction>::New();
  sample->SetImplicitFunction(sphere);
  sample->SetModelBounds(-.5, .5, -.5, .5, -.5, .5);
  sample->SetSampleDimensions(20, 20, 20);
  sample->ComputeNormalsOff();

  // contour
  auto surface =
    vtkSmartPointer<vtkContourFilter>::New();
  surface->SetInputConnection(sample->GetOutputPort());
  surface->SetValue(0, 0.0);

  //Create a mapper and an actor
  auto mapper =
    vtkSmartPointer<vtkPolyDataMapper>::New();
  mapper->SetInputConnection(surface->GetOutputPort());
  mapper->ScalarVisibilityOff();
  auto actor =
    vtkSmartPointer<vtkActor>::New();
  actor->SetMapper(mapper);
  actor->GetProperty()->EdgeVisibilityOn();
  actor->GetProperty()->SetColor(actorColor.GetData());
  actor->GetProperty()->SetEdgeColor(EdgeColour.GetData());

  // A renderer and render window
  auto renderer =
    vtkSmartPointer<vtkRenderer>::New();
  renderer->SetBackground(BackgroundColour.GetData());
  auto renderWindow =
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);
  auto renderWindowInteractor =
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  renderWindowInteractor->SetRenderWindow(renderWindow);
  //add the actor
  renderer->AddActor(actor);
  // Start
  renderWindow->Render();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(ImplicitSphere1)

find_package(VTK COMPONENTS 
  vtkCommonColor
  vtkCommonDataModel
  vtkFiltersCore
  vtkImagingHybrid
  vtkInteractionStyle
  vtkRenderingContextOpenGL2
  vtkRenderingCore
  vtkRenderingFreeType
  vtkRenderingGL2PSOpenGL2
  vtkRenderingOpenGL2 QUIET)
if (NOT VTK_FOUND)
  message("Skipping ImplicitSphere1: ${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(ImplicitSphere1 MACOSX_BUNDLE ImplicitSphere1.cxx )
  target_link_libraries(ImplicitSphere1 PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(ImplicitSphere1 MACOSX_BUNDLE ImplicitSphere1.cxx )
  target_link_libraries(ImplicitSphere1 PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS ImplicitSphere1
    MODULES ${VTK_LIBRARIES}
    )
endif () 

Download and Build ImplicitSphere1

Click here to download ImplicitSphere1 and its CMakeLists.txt file. Once the tarball ImplicitSphere1.tar has been downloaded and extracted,

cd ImplicitSphere1/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:

./ImplicitSphere1

WINDOWS USERS

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