Synergy between Slicer extension developers and VTK developers

Kitware is not only the lead developer of VTK, but we are also heavy users of it in our open-source applications, commercial consulting projects, and grant-funded research into scientific visaulization, informations, high-performance computing, computer vision, and medical image analysis.

Part of our commitment to the success of VTK and our other projects is indicated by the tutorials and open-acess developers meetings we host.  In this blog we describe a recent open-access developers meeting that we held to help bring together the VTK and the 3DSlicer communities.

Kitware is a primary developer of 3DSlicer, an open-source tool for medical image segmentation, registration and visualization. Using VTK, CTK, ITK, and CMake, as well as our software processes, it has become the de facto standard in research labs around the world and for rapidly prototyping commercial systems. In the last 12 months, it has been downloaded over 62,000 times.  3DSlicer has over 1,600 subscribers to its email lists.

On July 15th  2014, the Slicer extension developers had the opportunity to meet with the VTK core developers to discuss the upgrade of 3DSlicer and 3DSlicer’s extensions to VTK6.

To learn more about the new functionalities offered by VTK6, please read our previous blog post. To learn about transitioning your existing code to VTK6, please review the VTK 6 Migration Guide.


The hangout was hosted using the 3DSlicer BarCamp (a G+ community) and was orchestrated by Kitware’s Jean-Christophe Fillion-Robin [1].  It was very productive, and the main points discussed during that hangout are summarized below.

1) François Budin [2] had questions related to the transition of the ShapePopulationViewer extension that he developed for Slicer. Using the material previously presented on the VTK user maling list and illustrated in a gist, Dr. Berk Geveci [3] and Julien Finet [4]  were able to identify the problem and propose a solution. The input of the pipeline associated the “glyphMapper” was not up-to-date.

2) Nicole Aucoin [5] discussed with Dr. Berk Geveci [3] and Dr. Will Schroeder [6] how the existing VTK widget framework could be abstracted to facilitate the integration of VTK widgets in the Slicer displayable manager infrastructure. After reviewing Nicole’s proposal that was already presented on the VTK developer list, we concluded that as soon as a rough implementation is presented, a follow-up meeting would be scheduled.

3) Steve Pieper [7] asked a question related to the change in the VTK python wrapping.  It was triggering an error in the 3D Slicer continuous integration dashboard. Dr. Berk Geveci [3] explained that the python wrapping layer, maintained by Dr. David Gobbi [8], has been improved to output explicit messages when the type of data passed to a method was ambiguous.

Additionally, Dr. Berk Geveci [3] talked about the VTK6 roadmap for the coming years. This roadmap includes, but is not limited to, the following:

  • Transition to OpenGL 2 & 3 to better support mobile platforms and the removal of the fixed pipeline, while maintaining most of the API’s backward compatibility.

  • Introduction of a new volume mapper, already available for testing in VTK master.

  • Modernization of the widget interaction layer to support multi-touch interface, the Leap Motion interface, and a VR interface.

Moving forward, we plan on having several follow-on discussions for people who wish to contribute directly to VTK 6. The exact format of those open discussions is being determined.

We encourage all of those who are interested in our software libraries and applications to join the corresponding email lists.

If you would like to learn more about how Kitware can help your work via our software processes, applications, and research; please do not hesitate to contact


[1] Jean-Christophe Fillion-Robin is a lead developer of 3D Slicer and R&D engineer at Kitware Inc.

[2] François Budin is a research associate, at NIRAL, psychiatry departement at UNC

[3] Dr. Berk Geveci leads the scientific visualization and informatics teams at Kitware Inc.

[4] Julien Finet is a lead developer of 3D Slicer and an R&D engineer at Kitware Inc.

[5] Nicole Aucoin is a research associate at the Radiology department of Brigham and Women’s Hospital

[6] Dr. Will Schroeder is the president, CEO and co-founder of Kitware Inc.

[7] Dr. Steve Pieper is the Chief Architect of 3D Slicer and CEO of Isomics and Engineering Core Pi at the Neuroimage Analysis Center of Brigham and Women’s Hospital

[8] Dr. David Gobbi is the founder of Atamai Inc, a research scientist at Calgary Image Processing and Analysis Centre, and a research scientist at the Seaman Family MR Research Centre

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