VisIt is an Open Source, interactive, scalable, visualization, animation and analysis tool. From Unix, Windows or Mac workstations, users can interactively visualize and analyze data ranging in scale from small (<101 core) desktop-sized projects to large (>105 core) leadership-class computing facility simulation campaigns
The documentation is available in pdf format on the system, after having loaded the module, to the $MANPATH path.
You can find the documentation on the web at the original site