Defining messages for building blocks

The message posting feature allows you to have messages appear during a model simulation whenever a building block's value meets criteria that you define. For example, you can specify that a text message appears when a stock's value exceeds the value you define.

You can define multiple messages for a single entity to provide ongoing information to your users as the simulation progresses and the entity's value changes.

By using messages in your model, you can provide model users with information about model output while the simulation progresses. In addition, messages give you a way to coach model users toward a deeper understanding of model structure and behavior.

When defining messages, you can specify that the software displays text, pictures, movies, or sounds at the specified thresholds. You can also use message posting to navigate users to a specific location in the model (for example, a sequence of coaching screens).

Note: During the simulation run, any entities that have messages defined for them will post their messages when their threshold criteria have been met. All visible messages (text, pictures, and movies) appear in a message window, which floats above the model's surface. If you assign a sound only to the message, the model will pause and play the sound, but no visible message box appears.

To define a message, you first need to create one or more message stakes for an entity. A message stake defines the criteria for when the message should appear: the value threshold that triggers the message, and whether the entity's value must be greater or less than the value threshold.

For example, you might create a message stake for an entity that says that a message should appear when the entity's value drops below a value threshold of 50. You could also create a second message stake for the entity that appears when the entity's value rises above a value threshold of 100. Further, you can define multiple messages for each message stake, so that one message appears the first time the entity's value crosses a threshold, a second message appears when the entity's value crosses the same threshold, and so on.

After you create and define the criteria that triggers a message, you specify the type and content of the message that should appear (for example, the exact text, picture, sound, etc. to be displayed).

Tip: You can suppress all message posting for a model by selecting the Disable Posters check box in the Model Preferences dialog box.

To define a message for a building block

  1. On the model layer, select the building block (stock, flow, or converter) for which you want to define a message.
  2. Select the Messages panel.

  3. At the top of the panel, click in the message stake box to add a message threshold stake.

  4. Use the options beneath the message stake box to define a minimum and maximum value range and the criteria for when the message should be posted (for example, "Post the message when the entity's value becomes > 1000."). For detailed descriptions of these options, see Messages panel.

  5. With the message stake still selected, use the options under "Message Properties" select the type message you want to appear: Text Message or Media Message.

    Note: If you selected > or < in step 4, the message stake has a double-sided arrow head (). Each side can have a different set of messages. Click a side to highlight it, then define its message type and content.

  6. Use the rest of the options under "Message Properties" to define the content of the message (text, image, movie, sound, and/or navigation). For detailed descriptions of these options, see Messages panel.
  7. To define additional messages for the same message stake (for example, to have a different message appear the second time the message threshold is met), click the "Message 1" box and then select Add New. Use the options in the "Message Properties" section to define the second message. Repeat this step to define more messages for the message stake, as needed.
  8. Use the options under "Frequency" to specify how often per simulation run the message should appear.
  9. When you are finished defining the message stake, click in the bottom-right corner of the panels
  10. To create a new message stake for the selected entity, repeat steps 3-9.
  11. To define messages for a different entity, select the entity in the model diagram, then repeat steps 2-10.

To edit a message

You can edit the definition of any message you have already defined.

  1. On the model layer, select the building block (stock, flow, or converter) whose message you want to edit.
  2. Select the Messages panel.
  3. In the message stake box, select the message stake for the message that you want to edit. If the message stake has a double-sided arrow head (), select the side for which you want to edit messages.
  4. Use the options on the rest of the panel to edit the message. For detailed descriptions of these options, see Messages panel.
  5. When you are finished editing the message, click in the bottom-right corner of the panels.

To delete a message

You can delete a message stake (and all its associated messages), one or more messages defined for a single message stake, or all messages defined for an entity.

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