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Tutorial III 489
Animating a bank line
Open the 3D Bank Line Start model. (Unlike the final model, this model is set to open with- out opening the E3D window.)
3D Bank Line Start model
Animate the model in 2D
So that you can see some action in this model: Select the command Run > Show 2D Animation Run the model
Model particulars
In this model, customers enter the bank randomly, approximately one every 5 seconds. Gate blocks restrict access to the tellers so that each teller can have only one customer in front of them at a time; all other customers must wait in the Queue block.
When a teller becomes available, the first customer in the queue walks to that teller. The walk takes 5 seconds and Transport blocks (labeled Walk to Teller) are used to delay the customer for that amount of time. Activity blocks (labeled Transaction) represent the time it takes for the transaction with the teller. The transaction time is specified by a triangular distribution with a minimum of 2, a maximum of 10, and a mostly likely time of 5. After finishing the transaction, the customer exits the bank.
Differences from typical discrete event models
If you are familiar with discrete event modeling, you may notice some differences between this model and a typical single queue/two server model:
1) ThelocationargumentfortheexponentialdistributionintheCreateblock(labeledPeople Arrive) is 1. In many discrete event models the location argument is left blank for expedi- ency. For this model, a location value of 1 ensures that the interarrival time can never be too close to zero – there will always be at least one second between item arrivals. The real- life correlation is that people don’t walk through a door at exactly the same time.
2) Thetimeittakesacustomertowalkfromthewaitingareatoatellerisexplicitlyrepre- sented by a Transport block (labeled Walk to Teller). In many discrete event models, the travel time would not be considered significant or would be just added to the time it takes to perform the transaction. This model takes travel time into consideration, because for 3D animation you want to see the customers moving from the waiting area to the teller.

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