VISUALIZATION AND ANIMATION

6.5 VISUALIZATION AND ANIMATION

Arena provides support for visualization of models and animation of simulation runs. These may be used to observe and monitor the temporal evolution of the model’s state

and statistics in the course of a run. Such observation and monitoring activities are used both to debug the model and to understand various phenomena occurring in it. We now proceed to describe the main animation facilities in Arena.

6.5.1 A NIMATE C ONNECTORS B UTTON

The Run Interaction toolbar includes the Animate Connectors button. When clicked, this button enables the motion of entities among modules. Entity objects are represented either by default pictures or user-assigned pictures. Tracking the motion of a target entity on the model canvas in the course of a run aids in verifying model logic.

6.5.2 A NIMATE T OOLBAR

Figure 6.4 displays the Animate toolbar, which supports visualization and animation of dynamic data values over time. This toolbar consists of nine buttons as follows (from left to right):

Model Testing and Debugging Facilities 119

Figure 6.4 Arena Animate toolbar.

The Clock button pops up a dialog box that permits the modeler to initialize a “clock” and start it running. The Date button pops up a dialog box that permits the modeler to initialize a calendar and start it running, showing the current date. The Variable button pops up a dialog box that permits the modeler to specify an expression and its format. The value of that expression is maintained up to date over the simulation run. The Level button pops up a dialog box that permits the modeler to specify and display the same information as the Variable button, but as a graphical analog “level.” This is useful in tracking the value of a bounded expression in order to see at a glance the current relative magnitude. An example is resource utilization (bounded by 0 and 1), which is specified by typing DAVG(Dstat ID) in the Expression field of the dialog box, where DAVG (Dstat ID) stands for the average of the Time-Persistent statistic whose Arena number is Dstat ID. Similarly, the expression TAVG(Tally ID) is used to tally the average value collected by the Tally statistic whose Arena number is Tally ID. The Histogram button pops up a dialog box that permits the modeler to specify histogram collection on a specific expression over time during a simulation run. The Plot button pops up a dialog box that permits the modeler to specify a plot of the value of an expression over time during a simulation run. The Queue button pops up a dialog box that permits the modeler to specify a queue and display its size over time during a simulation run as a standard T-bar (see Section 5.2). The Resource button pops up a dialog box that permits the modeler to specify a user- defined resource and display its states over time during a simulation run. A resource can be identified on screen by its icon, which is provided by an Arena default, but may

be graphically edited by the modeler. The Global button pops up a dialog box that permits the modeler to specify a finite- valued expression, and to display its value over time via icons during a simulation run.

6.5.3 A NIMATE T RANSFER T OOLBAR

The Animate Transfer toolbar supports visualization and animation of various transportation devices, such as conveyors, forklifts, AGVs (automatic guided vehicles), and so on. This toolbar will be revisited and explained in Chapter 13.