By default VAPOR GUI expects data to have evenly spaced time steps. The Animation tab provides a constant "frame step size" for animating forward and backwards in time. The Flow panel Unsteady flow time settings provides a constant time step increment for sampling data over time.
It may occur that the data present in the VDC is spaced at nonuniform time steps, for example if the data to be visualized was irregularly sampled from a larger data set. To easily step through such data and perform unsteady flow integration, users may specify exactly the set of time steps that are to be sampled. In the Animation panel, under "Explicit Time Step Control", users may specify a list of time steps that will be sampled. The "rebuild" button constructs a time step list based on the time steps available in the current VDC. Individual entries can be added to or deleted from the list using the "Add" or "Delete" buttons. When the check box "Use Explicit Time Steps" is checked, the animation will only play the time steps in the list. The list will be saved in a session file so that it does not need to be retyped the next time you visualize your data.
There is a similar capability for performing unsteady flow integration on data with nonuniform time step spacing, in the Unsteady flow time settings. A list of time steps can be constructed and edited. When "Use time step list" is checked, only the time steps in the list will be sampled during unsteady flow integration.
