The Tomviz project is developing a cross platform, open source application for the processing, visualization, and analysis of 3D tomographic data. It features a complete pipeline capable processing data from alignment, reconstruction, and segmentation through to displaying, visualizing, and interacting with 3D reconstructions of tomographic data. Many of the data operators are available as editable Python scripts that can be modified in the interface to experiment with different techniques. The pipeline can be saved to disk, and a number of common file formats are supported for importing and exporting data. The Tomviz project was founded by Marcus D. Hanwell and Utkarsh Ayachit at Kitware, David A. Muller (Cornell University), and Robert Hovden (University of Michigan), funded by DOE Office of Science contract DE-SC0011385.