The Volumetric Basic - Interval page offers selections of time-related options.
For Analysis Interval, you can leave the default from the scenario or click 
to access the Interval selector from the Analysis Workbench capability for other options.
To evaluate a spatial calculation on a volume grid over a specified time interval, choose one of the following options:
- At an instant in time: You need not provide further specification.
When you select this option, STK will not save computed data, regardless of your selection under Save Computed Data on the Basic - Advanced properties page.
- At times from a Time Array: Click to access the Time Array selector from the Analysis Workbench.
- At times at step size: Enter the step size time.
Selecting any of these options causes a reevaluation of the new volumetric data over time and across the grid.