NA-MIC, 2008 June Workshop, IHK Akademie Westerham

VTK

Sebastien BARRE, Ph.D. - Kitware, Inc.

June 16-17, 2008 NA-MIC, 2008 June Workshop, IHK Akademie Westerham 2

VTK domain: Visualization

• A definition for visualization• Map data or information into images or other sensory input

(touch, sound, smell, taste)• Engages human perception system• Simple, effective powerful

• Complex data• Voluminous data

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VTK: The Visualization Toolkit

• Began with a textbook (work began 1993 – 1st edition 1995)

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What is VTK?

• A visualization toolkit• Designed and implemented using object-oriented principles• C++ class library (nearly 1,000,000 LOC)• Automated Java, Tcl, Python bindings• Portable across Unix, Windows, MacOSX• Supports 2D/3D graphics, visualization, image processing,

volume rendering, infoviz, geoviz• 2500+ user mailing list; 40+ active developers• World-wide academic, commercial, government users• Basis of college undergraduate and graduate courses• Free (BSD-like license)

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VTK is not a system

• Embeddable• Plays with other software

• Separable• Can pull out “pieces”

• Adaptable• Not dependent on GUI• Not dependent on rendering library

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Building applications with VTK

• Applications can be created using• C++ (compiled language)• Tcl (interpreted language)• Java (interpreted language)• Python (interpreted language)

• Interpreted Languages• Have GUI support• Easy to prototype with• Slower than compiled C++

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vtkPolyData

vtkImageData

vtkStructuredGrid

vtkUnstructuredGrid

vtkRectilinearGrid

DataSet types

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Examples

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Surface rendering

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Volume rendering

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Image processing

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Information visualization

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Interaction Widgets

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Instances of render window (vtkRenderWindow)

Actor instances(vtkActor)

Renderer instances(vtkRenderer)

The VTK graphics subsystem

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A VTK scene consists of:• vtkRenderWindow - contains the final image• vtkRenderer - draws into the render window• vtkActor - combines properties / geometry• vtkLight - illuminate actors• vtkCamera - renders the scene• vtkPolyDataMapper - represents geometry• vtkTransform - position actors

The VTK graphics subsystem

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sphere source

polydata mapper

actor

renderer

render window

render window interactor

VTK « Hello world »

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vtkSphereSource *sphere = vtkSphereSource()::New(); // create data pipeline vtkPolyDataMapper *sphereMapper = vtkPolyDataMapper::New();sphereMapper->SetInputConnection(sphere->GetOutputPort());

vtkActor *sphereActor = vtkActor::New();sphereActor->SetMapper(sphereMapper); //mapper connects actor with pipeline

vtkRenderer *renderer = vtkRenderer::New();vtkRenderWindow *renWin = vtkRenderWindow::New();renWin->AddRenderer(renderer);

vtkRenderWindowInteractor *iren = vtkRenderWindowInteractor::New();iren->SetRenderWindow(renWin);

renderer->AddViewProp(sphereActor);renderer->SetBackground(1,1,1);renWin->SetSize(300,300);

renWin->Render();iren->Start(); //starts the event loop

VTK « Hello world » (C++)

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Find more about VTK…

• Online documentation• http://vtk.org• Wiki• FAQ• Manual pages (Generated by doxygen)• search the archive of the mailing lists

• Source code• Embedded documentation in header files *.h• Examples/ and Testing/ directories

• Books• VTK Textbook• VTK User's Guide