[vtkusers] How do I save all slices of a volume from vtkCutter to another canvas?

[Magnus Elden]

I tried following the advice I was provided, but using reslice and using the cutter to get a single cut end up with nothing for the reslice and a blank plane for the cutter.

If I render the volume by itself it works fine, but I only need a single slice of that volume with the transfer functions. I have been able to save an image to another canvas, so all I need is a xPixels*yPixels image rendered so that I can copy it into its slot on the big canvas.

Below you have the minimum code that ever rendered anything for me. I followed the examples as best I could, but I was unable to make sense of this.



       vtkSmartPointer<vtkImageData> imageData =
              vtkSmartPointer<vtkImageData>::New();
       vtkSmartPointer<vtkXMLImageDataReader> reader =
              vtkSmartPointer<vtkXMLImageDataReader>::New();
       reader->SetFileName(path.c_str());
       reader->Update();
       reader->GetOutput()->Register(reader);
       imageData->ShallowCopy(reader->GetOutput());

       double bounds[6];
       reader->GetOutput()->GetBounds(bounds);//Get the bounds of the volume. X0x1, y0y1, z0z1

       vtkSmartPointer<vtkPlane> plane =
              vtkSmartPointer<vtkPlane>::New();//This plane is used to define the cutting plane.
       plane->SetOrigin(0, 0, 0);
       plane->SetNormal(0, 1, 0);

       // Create model actor

       vtkSmartPointer<vtkLookupTable> lut =
              vtkSmartPointer<vtkLookupTable>::New();//This seems to be required to render anything at all.
       lut->SetRange(0.3, 1); // image intensity range
       lut->SetValueRange(0.3, 1.0); // from black to white
       lut->SetSaturationRange(0.3, 1.0); // no color saturation
       lut->SetTableRange(0.2, 1.0);
       lut->SetRampToLinear();
       lut->SetBelowRangeColor(1, 1, 1, 1);
       lut->Build();

       vtkSmartPointer<vtkCutter> cutter =
              vtkSmartPointer<vtkCutter>::New();//The object doing the cutting for us.
       cutter->SetInputConnection(reader->GetOutputPort());
       cutter->SetCutFunction(plane);
       cutter->GenerateValues(1, 0.1, 0.1);

       vtkSmartPointer<vtkImageReslice> reslice =
              vtkSmartPointer<vtkImageReslice>::New();//No idea what this is supposed to do.
       reslice->SetOutputExtent(0, 600, 0, 600, 0, 0);
       reslice->SetInputData(reader->GetOutput());
       reslice->Update();

       vtkSmartPointer<vtkPolyDataMapper> cutterMapper =
              vtkSmartPointer<vtkPolyDataMapper>::New();
       cutterMapper->SetInputConnection(cutter->GetOutputPort());//Change betweent he cutter and reslice here
       cutterMapper->SetLookupTable(lut);
       cutterMapper->UseLookupTableScalarRangeOn();

       // Create cut actor
       vtkSmartPointer<vtkActor> sliceActor =
              vtkSmartPointer<vtkActor>::New();
       sliceActor->SetMapper(cutterMapper);

Thank you for your time.

Yours,
Magnus Elden


From: Sankhesh Jhaveri [mailto:sankhesh.jhaveri at kitware.com]
Sent: Monday, 12 September, 2016 15:36
To: Magnus Elden <magnus_elden at hotmail.com>
Cc: vtkusers at vtk.org
Subject: Re: [vtkusers] How do I save all slices of a volume from vtkCutter to another canvas?

Hi Magnus,

First of all, if the goal is to just slice the volume consider using vtkImageReslice (http://www.vtk.org/Wiki/VTK/Examples/Cxx/ImageData/ImageReslice) instead of vtkCutter.

You can simply set the output image data of the vtkImageReslice to a vtkImageActor and add it to a vtkRenderer as in http://www.vtk.org/Wiki/VTK/Examples/Cxx/Images/InteractWithImage

Hope that helps.



Sankhesh Jhaveri
Sr. Research & Development Engineer | Kitware<http://www.kitware.com> | (518) 881-4417




On Sat, Sep 10, 2016 at 8:01 PM, Magnus Elden <magnus_elden at hotmail.com<mailto:magnus_elden at hotmail.com>> wrote:
I have a volume that the class vtkCutter cuts into n slices. Now I need to save a render of each slice to another larger canvas to generate something similar to this: http://previews.123rf.com/images/bunyos/bunyos1403/bunyos140300039/26777884-MRI-scan-of-the-human-brain-Stock-Photo.jpg

I am able to render it by linking the cutter output to a mapper and then into a vtkActor that I add to the renderer, but I have no idea how I can render each slice to a canvas. In the worst case I just want the renders to be all stored to disk.

Thank you for your help.

Yours,
Magnus Elden

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