visit

VisIT (http://visit.llnl.gov) is

• a free [and open-source], interactive parallel visualization and graphical analysis tool for viewing scientific data on Unix and PC platforms [Windows, Mac OS].
• users can quickly generate visualizations from their data, animate them through time, manipulate them, and save the resulting images for presentations
• VisIt can be used to visualize scalar and vector fields defined on two- and three-dimensional (2D and 3D) structured and unstructured meshes.
• VisIt was designed to handle very large data set sizes in the terascale range and yet can also handle small data sets in the kilobyte range

Basic concepts

• plots (ways to render data): > 20
• pseudocolor, volume-rendering, contour, vector, scatter, ...
• operators (ways to manipulate data, ”filters”): > 40
  • isosurface, isovolume, clip, slice, project, (coordinate-)transforms, ...
• file format readers (ways to import data): > 80
  • Gaussian cube, PDB, HDF5/XDMF, NetCDF, (common CFD fmts), VTK, BOV,...
• queries (ways to extract quantitative information): > 50
  • expressions (ways to create derived quantities)
  • simple expression syntax: math, logical, relational, mesh, …
  • Python syntax
• other features/utilities (not fully covered here)
  • movie generation: simple, keyframing
  • session management: save/restore status of interactive session
  • it-situ visualisation: instrumentation of simulation codes

Intuitive concept of a visualization “pipeline”

• Plots: pseudocolor, volume, vector, …
• and Operators: isosurface, transform (e.g. coordinate), clip, box, revolve, …
• options for plots and operators (double-click or pull down menu)
• multiple (successive) operators per plot
• hint: for performance reduce as early as possible, e.g.:1: box, 2: transform (not vice versa)
• multiple plots per window

[[visitGUI1.png|align=right|float|width=500px]]

• Example: isosurface of a scalar variable F(x,y,z) colored by the value of another scalar variable G(x,y,z) (F, G are defined on the same mesh):
  1. create pseudocolor plot for G
  2. apply isosurface operator for F (instead of default: G)

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GUI

Molecular data features

In recent years, support in VisIt has grown greatly in the areas of atomic and molecular visualization and analysis. This comes in the form of internal data model support, new plots and operators, new and upgraded analysis features, a basic understanding of atomic characteristics, and a variety of file format readers. See www.visitusers.org/index.php?title=Molecular_data_features