VisIt

"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. Users can quickly generate visualizations, animate them through time, manipulate them with a variety of operators and mathematical expressions, and save the resulting images and animations for presentations. VisIt contains a rich set of visualization features to enable users to view a wide variety of data including scalar and vector fields defined on two- and three-dimensional (2D and 3D) structured, adaptive and unstructured meshes. Owing to its customizeable plugin design, VisIt is capabable of visualizing data from over 120 different scientific data formats.

The basic design is a client-server model, where the server is parallelized. The client-server aspect allows for effective visualization in a remote setting, while the parallelization of the server allows for the largest data sets to be processed reasonably interactively. The tool has been used to visualize many large data sets, including a two hundred and sixteen billion data point structured grid, a one billion point particle simulation, and curvilinear, unstructured, and AMR meshes with hundreds of millions to billions of elements. The most common form of the server is as a stand alone process that reads in data from files. However, an alternate form exists where a simulation code can link in "lib-VisIt" and become itself the server, allowing for in situ visualization and analysis.

VisIt follows a data flow network paradigm where interoperable modules are connected to perform custom analysis. The modules come from VisIt's five primary user interface abstractions and there are many examples of each. There are twenty one ``plots" (ways to render data), forty-two ``operators" (ways to manipulate data), eighty-five file format readers, over fifty ``queries" (ways to extract quantitative information), and over one hundred ``expressions" (ways to create derived quantities). Further, a plugin capability allows for dynamic incorporation of new plot, operator, and database modules. These plugins can be partially code generated, even including automatic generation of Qt and Python user interfaces.

VisIt also supports C++, Python and Java interfaces. The C++ and Java interfaces make it possible to provide alternate user interfaces for VisIt or allow existing C++ or Java applications to add visualization support. The Python scripting interface gives users the ability to batch process data using a powerful scripting language. This feature can be used to create extremely sophisticated animations or implement regression suites. It also allows simulation systems that use Python as a back-plane to easily integrate visualization capabilities into their systems."

https://wci.llnl.gov/simulation/computer-codes/visit

http://www.visitusers.org/index.php?title=Main_Page