Displaying time-dependent data is a common requirement for GIS applications. In conjunction with the Real-time Engine component of LuciadLightspeed, Lucy provides support to implement this. The Real-time Engine component of LuciadLightspeed provides the base functionality. As such, it is required to make use of this feature of Lucy.

The central class in the Real-time Engine component is the TLcdSimulator class. This class can keep track of the current time in the application, modify the current time of the application, and pass the current time to the time-dependent models. It is up to the models to update their state to match the current time in the application.

A time-dependent model is an ILcdModel that also implements the ILcdMultiDimensionalModel interface and exposes a java.util.Date dimension. When such a model is added to a view in Lucy, the TLcdSimulator contained in the TLcyPreviewAddOn picks up this model, and keeps the current date on the model in-sync with the current date of the application.