A time-varying database (a ".visit" file or virtual database) is opened the same way as a database with a single time step. A time varying database is created by either grouping files into a ".visit" file in the File Selection Window or by turning on automatic file grouping so VisIt creates virtual databases, which are databases made up of multiple single time step databases that have similar filenames. To open a time-varying database, click on it to highlight it and then click the Open button in the File panel. Double-clicking the time-varying database also will open it. The one difference between opening a single time step database and a time-varying database is that if the time-varying database is also a virtual database then it can be opened at a later time step without having to first open it at the first time step.
The File panel displays time varying databases with a green database icon next to the name of the database. There often is also a small check box next to the database icon that expands to show the database's time steps. This is shown in figure. When a time- varying database is open, the animation controls are activated so any time step in the database can be used. Note that the animation controls are only active when visualizing a time-varying database or when VisIt is in keyframe animation mode.