The Visualization Toolkit (VTK) is an open-source, freely available software system for 3D computer graphics, modeling, image processing, volume rendering, scientific visualization, and information visualization. VTK also includes ancillary support for 3D interaction widgets, two- and three-dimensional annotation, and parallel computing. At its core, VTK is implemented as a C++ toolkit, requiring users to build applications by combining various objects into an application. The system also supports automated wrapping of the C++ core into Python, Java, and Tcl, so VTK applications may also be written using these interpreted programming languages.

VTK employs Kitware’s Quality Software Process (CMake, CTest, CDash, and CPack) to build, test, and package the system, making VTK a cross-platform application dependent on test-driven development and extreme programming, and enabling the application to produce high-quality, robust code. VTK is used world-wide in commercial applications, as well as in research and development. It is the basis for many advanced visualization applications such as ParaView, VisIt, VisTrails, Slicer, MayaVi, and OsiriX.

The Origins of VTK

VTK was originally written as part of the textbook The Visualization Toolkit An Object-Oriented Approach to 3D Graphics. Will Schroeder, Ken Martin, and Bill Lorensen, three graphics and visualization researchers, wrote the book and companion software on their own time, beginning in December 1993, and with legal permission from their then employer, GE Corporate R&D. The motivation for the book was to collaborate with other researchers and develop an open framework for creating leading-edge visualization and graphics applications. VTK grew out of the authors’ experiences at GE, particularly with their experience with the LYMB object-oriented graphics system. Other influences included the VISAGE visualization system developed by Schroeder et. al, the Clockworks object-oriented computer animation system developed at RPI, and the very successful object-oriented modeling book Object-Oriented Modeling and Design, on which Bill Lorensen is co-author.

After the core of VTK was written, users and developers around the world began to improve and apply the system to real-world problems. In particular, GE Medical Systems and other GE businesses graciously contributed to the system. Some researchers, such as Dr. Penny Rheinghans, began to teach with the book. Other early supporters included Jim Ahrens at Los Alamos National Labs and unnamed, but generous, oil and gas supporters. In recent years, Sandia National Labs have been strong supporters and co-developers with particular focus on adding information visualization to VTK.

To support what was becoming a large, active, and world-wide VTK community, Ken and Will, along with Lisa Avila, Charles Law and Bill Hoffman, left GE Research to found Kitware, Inc. in 1998. Since that time, hundreds of additional developers have created what is now the premier visualization system in the world.