Simulating > The Model Entity

Every Ventity model automatically includes a single model entity called Model. Defined in that entity are four variables:

Initial Time	The model time at the start of the simulation.
Final Time	The model time at which the simulation ends.
Time	The time variable for the model.
Time Step	The duration of one time slice. The amount by which time advances during each calculation round.

The values of the four variables are determined by the Run Configuration. The Model entity is singular, so other entities can access these variables without creating a reference. To use time in an equation, you would enter Model.time. To use final time, enter Model.final time.

You may add other properties (variables, attributes, ...) to the model entity as you need, just as with any other entity type. If you add policy start time to the model entity, then any other entity in the model may use Model.policy start time in equations.

Style Tip: We recommend reserving the model entity for constructs that are more related to the control and execution of the calculation than about the objects and ideas represented by the model. For example, switches to turn various model elements on or off for a simulation could be defined in the model entity. Used in this way, the Model entity really represents the modeler, or more specifically, the choices the modeler is making about defining a particular run.

If instead you are trying to arrange for information about the system you are modeling to be globally accessible by many other entities, it is best to set up a separate entity to hold those. See singular entities for more information.