VisIt home page

Welcome to VisIt's main help page. VisIt is a distributed, parallel, visualization tool for visualizing data defined on two- and three-dimensional structured and unstructured meshes. VisIt's distributed architecture allows it to leverage both the compute power of a large parallel computer and the graphics acceleration hardware of a local workstation. Another benefit of the distributed architecture is that VisIt can visualize the data where it is generated, eliminating the need to move the data. VisIt can be controlled by a Graphical User Interface (GUI) or through the Python or Java programming languages.

## Key Features

Feature | Description/Example
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Has rich feature set for scalar, vector, and tensor field visualization | VisIt’s visualization capabilities are primarily grouped into two categories: Plots are used to visualize data and include Boundary, Contour, Curve, Mesh, Pseudocolor, Scatter, Streamline, Surface, Tensor, Truecolor, Vector, and Volume. Operators transform the data prior to visualization. Some examples include Slice, Index select, Iso-surface, Onion peel, Reflect, Threshold. See the chapter on operators for the complete list of operators that VisIt supports. VisIt handles 2D and 3D data equally well. VisIt also has the ability to animate data, allowing users to see the time evolution of their data.
Reads many popular data file formats | VisIt can natively read many file formats, without the help of any translator utility. Some examples of the data file formats that VisIt can read are: Alias Wavefront OBJ, BOV, Boxlib, Ensight Gold, ESRI Shapefile, Exodus, Image (bmp, jpeg, png, rgb, tiff), PLOT3D, SAMRAI, SAR, Silo, Spheral, STL, TecPlot, VTK. VisIt reads many more types of files and can easily be extended to read other types of files by writing database reader plugins.
Provides qualitative and quantitative visualization and analysis | VisIt is also a powerful analysis tool. It provides support for derived fields, which allow new fields to be calculated using existing fields. For example, if a dataset contains a velocity field, it is possible to define a new field that is the velocity magnitude. VisIt’s quantitative analysis tools include: Line-out, which allows you to create curves from higher dimensional datasets by interactively defining lines using the mouse. Pick and query, which allows you to query the dataset by clicking on images. VisIt also supports a generalized query interface, which allows you to query derived quantities such as volume or surface area.
Supports multiple mesh types | VisIt provides support for a wide range of computational meshes, including two- and three-dimensional rectilinear, curvilinear, unstructured , and AMR meshes.
Powerful, full-featured graphical user interface (GUI) | VisIt’s graphical user interface allows novice users to quickly get started visualizing their data, as well as allowing power users access to advanced features. VisIt automatically creates time-based animations from data sets that contain multiple time steps. In addition, it also has a keyframe animation capability that allows users to create sophisticated animations. VisIt allows users to pan, zoom, and rotate objects interactively using the mouse. It also gives users the ability to interactively size and position geometric objects such as planes and spheres.
Parallel and distributed architecture for visualizing terascale data sets | VisIt employs a distributed and parallel architecture in order to handle extremely large data sets interactively. VisIt’s rendering and data processing capabilities are split into viewer and engine components that may be distributed across multiple machines: Viewer—Responsible for rendering and is typically run on a local desktop or visualization server so that it can leverage the extremely powerful graphics cards that have been developed in the last few years. Engine—Responsible for the bulk of the data processing and input/output (I/O) and is typically run on a remote machine where the data is located. This eliminates the need move the data and makes high-end compute and I/O resources available to it. The engine can be run serially on a single processor or in parallel on thousands of processors.
Interfaces with C++, Python, and Java | 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.
Extensible with dynamically loaded plug-ins | VisIt achieves extensibility through the use of dynamically loaded plugins. All of VisIt’s plots, operators, and database readers are implemented as plugins and are loaded at run-time from the plugin directory. New plugins can be added simply by installing them in this directory. VisIt comes with a graphical plugin creation tool, which greatly simplifies the process of creating new plugins. The user describes the properties of the plugin and then the tool generates most of the code necessary to implement the plugin. For example, in the case of an operator, the plugin creation tool creates the code necessary for the graphical user interface attribute window; the C++, Python, and Java interfaces; and the code necessary to interface to VisIt. The only code you need to write is the C++ code that actually performs the operation.
Multi-platform support | VisIt operates on UNIX (Irix, Tru64, AIX, Linux, Solaris), Windows, and MacOS X platforms. Software for these platforms can be downloaded at ftp://ftp.llnl.gov/pub/visit.
Open-source code | VisIt's code is open source, allowing programmers to read, redistribute, and modify the source code.
Customer support | Send e-mail regarding VisIt to visit-users@ornl.gov. LLNL users can dial extension 4-2VIS during normal working hours (8am-5pm PST) to reach the VisIt help desk.

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