[vtkusers] How to extract a region using a box?

[kenichiro yoshimi]

Hello Polly,

It may be helpful to get the bounds of the polydata by GetBounds()
method because vtkBox is defined with bounds. In the case that uses
fran_cut.vtk, there is something like below.
---
  double bounds[6];
  auto fran_cut = vtkPolyData::SafeDownCast(reader->GetOutput());
  fran_cut->GetBounds(bounds);

  vtkSmartPointer<vtkTransform> transform =
    vtkSmartPointer<vtkTransform>::New();
  transform->PreMultiply();
  transform->RotateZ(0.0);
  transform->RotateY(0.0);
  transform->RotateX(0.0);
  transform->Scale(1, 0.4, 1);
  transform->Translate(0, 0, 0);

  vtkSmartPointer<vtkBox> box =
    vtkSmartPointer<vtkBox>::New();
  box->SetBounds(bounds);
  box->SetTransform(transform);
---

Besides, if it is difficult for you to adjust the transform values
that you applied in ParaView, you might as well use Python scripting
in ParaView. In that case, you are more likely to get a better answer
if you post to the ParaView discussion forum:
https://discourse.paraview.org/

Thanks
2018年8月14日(火) 1:00 Polly Pui <polly_sukting at hotmail.com>:
>
>
> Hi,
> I tested using the values below with fran_cut.vtk but I failed to get the area.
> Please advice. Thank you so much!
>
> vtkSmartPointer<vtkTransform> transform =
> vtkSmartPointer<vtkTransform>::New();
> transform->PreMultiply();
> transform->RotateZ(0.0);
> transform->RotateY(0.0);
> transform->RotateX(0.0);
> transform->Translate(0.5, -10.0, -590.0);
> transform->Scale(0.5, 0.2, 0.6);
> vtkSmartPointer<vtkBox> box =
> vtkSmartPointer<vtkBox>::New();
> box->SetBounds(-1.0, 1.0, -1.0, 1.0, -0.6, 0.6);
> box->SetTransform(transform);
>
>
>
> ________________________________
> From: kenichiro yoshimi <rccm.kyoshimi at gmail.com>
> Sent: Saturday, August 11, 2018 11:08 AM
> To: polly_sukting at hotmail.com
> Cc: vtkusers
> Subject: Re: [vtkusers] How to extract a region using a box?
>
> Hi,
>
> The Filter>Extract Cells By Region in ParaView uses vtkExtractGeometry
> class internally. So the following example may be helpful to automate
> polygon extractions with a specified box.
>
> --- ExtractGeometry.cxx ---
> #include <vtkBox.h>
> #include <vtkCamera.h>
> #include <vtkDataSetMapper.h>
> #include <vtkExtractGeometry.h>
> #include <vtkProperty.h>
> #include <vtkRenderer.h>
> #include <vtkRenderWindow.h>
> #include <vtkRenderWindowInteractor.h>
> #include <vtkSmartPointer.h>
> #include <vtkSphereSource.h>
> #include <vtkTransform.h>
>
> int main (int, char *[])
> {
>   vtkSmartPointer<vtkSphereSource> sphere =
>     vtkSmartPointer<vtkSphereSource>::New();
>   sphere->SetRadius(0.5);
>   sphere->SetPhiResolution(50);
>   sphere->SetThetaResolution(50);
>   sphere->Update();
>
>   vtkSmartPointer<vtkTransform> transform =
>     vtkSmartPointer<vtkTransform>::New();
>   transform->PreMultiply();
>   transform->RotateZ(30.0);
>   transform->Translate(0.5, 0.0, 0.0);
>
>   vtkSmartPointer<vtkBox> box =
>     vtkSmartPointer<vtkBox>::New();
>   box->SetBounds(-0.5, 0.5, -0.5, 0.5, -0.5, 0.5);
>   box->SetTransform(transform);
>
>   vtkSmartPointer<vtkExtractGeometry> extractGeometry =
>     vtkSmartPointer<vtkExtractGeometry>::New();
>   extractGeometry->SetInputData(sphere->GetOutput());
>   extractGeometry->SetImplicitFunction(box);
>   extractGeometry->ExtractInsideOn();
>   extractGeometry->ExtractBoundaryCellsOn();
>
>   vtkSmartPointer<vtkDataSetMapper> mapper =
>     vtkSmartPointer<vtkDataSetMapper>::New();
>   mapper->SetInputConnection(extractGeometry->GetOutputPort());
>
>   vtkSmartPointer<vtkActor> actor =
>     vtkSmartPointer<vtkActor>::New();
>   actor->SetMapper(mapper);
>   actor->GetProperty()->SetColor(0.8900, 0.8100, 0.3400);
>
>   // Create graphics stuff
>   //
>   vtkSmartPointer<vtkRenderer> ren =
>     vtkSmartPointer<vtkRenderer>::New();
>   ren->SetBackground(.3, .4, .6);
>
>   vtkSmartPointer<vtkRenderWindow> renWin =
>     vtkSmartPointer<vtkRenderWindow>::New();
>   renWin->AddRenderer(ren);
>   renWin->SetSize(512,512);
>
>   vtkSmartPointer<vtkRenderWindowInteractor> iren =
>     vtkSmartPointer<vtkRenderWindowInteractor>::New();
>   iren->SetRenderWindow(renWin);
>
>   // Add the actors to the renderer, set the background and size
>   //
>   ren->AddActor(actor);
>
>   // Generate an interesting view
>   //
>   ren->ResetCamera();
>   ren->GetActiveCamera()->Azimuth(120);
>   ren->GetActiveCamera()->Elevation(30);
>   ren->GetActiveCamera()->Dolly(1.0);
>   ren->ResetCameraClippingRange();
>
>   iren->Initialize();
>   iren->Start();
>
>   return EXIT_SUCCESS;
> }
>
> --- CMakeLists.txt ---
> cmake_minimum_required(VERSION 2.8)
>
> PROJECT(ExtractGeometry)
>
> find_package(VTK REQUIRED)
> include(${VTK_USE_FILE})
>
> add_executable(ExtractGeometry MACOSX_BUNDLE ExtractGeometry.cxx )
>
> target_link_libraries(ExtractGeometry ${VTK_LIBRARIES})
> ---
>
> Regards
> 2018年8月9日(木) 16:51 Polly Pui <polly_sukting at hotmail.com>:
> >
> > Hi,
> >
> > Can anyone please tell me how can I do extract a region by providing a box (which we can set the size of it) on a polydata?
> >
> > I could do it manually in Paraview by selecting the Filter>Extract Cells By Region.
> >
> > However, I have more than 1000 dataset. It is time consuming if I apply it manually for each dataset.
> >
> >
> > Thanks!
> >
> >
> > Best,
> >
> > Polly
> >
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