Model Build Toolbar

Use the Model Build toolbar to add building blocks to your model.

Stock

Click this tool to create a stock; select from the dropdown menu to choose from different stock types. A stock is an accumulation. It collects whatever flows into it, minus whatever flows out of it.

Flow

Click this tool to create a flow; select from the dropdown menu to choose from different flow types. A flow fills and drains accumulations. The unfilled arrow head on the flow pipe indicates the direction of positive flow.

Converter

Click this tool to create a converter; select from the dropdown menu to choose from different converter types. A converter holds values for constants, defines external inputs to the model, calculates algebraic relationships, and serves as the repository for graphical functions. In general, it converts inputs into outputs.

Action Connector

Click this tool to create a connector; select from the dropdown menu to choose from different connector types. A connector connects model variables to each other.

Module/ Sector

Click this tool to add a module, or select from the dropdown menu to add a sector.

Modules are self-contained models that you can connect to other models. Modules make it possible to break a single model into well-defined "chunks". Each module within a model is a cohesive model on its own, which you can run separately or within the larger model.

Use a sector to group functionally-related building blocks in a model. For example, in a model of a business organization, you might use a sector to represent each of the major processes under consideration; you might have a manufacturing sector, a marketing sector, a human resources sector, and a financial sector in the model. In a model of a food web, each of the major trophic levels might be represented by a different sector.

Graph

Click this tool to add a graph. Use graphs to plot data generated by model simulations. Select from the dropdown menu to choose from three basic types of graphs:

• time series plots (X, Y, Z over time)
• scatter plots (X vs. Y)
• bar graphs

Table

Click this tool to add a table. Use tables to display numerical output from one or more variables in your simulation.

Numeric Display

Click this tool to add a numeric display. Use a numeric display object to display the current output value for the associated model variable. Numeric displays are useful for getting a precise reading of what's going on in the model as a simulation unfolds.

Text Box

Click this tool to add a text box. Use text boxes to display text in your model. You can use text boxes to add labels, instructions, and explanatory text right on the model diagram.

Graphics Box

Click this tool to add a graphics box. Graphics boxes give you the ability to use visual elements to organize and annotate your model. You can use a graphics box to frame part of the model. You can also add images or other graphics, like maps, floor plans, or mechanical drawings, and use them as backgrounds for parts of your model.

Ghost

Click this tool to use the ghost tool. Use the ghost tool to create variable aliases. Variable aliases help you keep your diagrams tidy by letting you use the same variable in separate locations in your model. This helps keep connections neat, when a direct connection would cause arrows to cross.

See Also