Insight Maker logoInsight Maker is a free online systems modelling software.  The online software provides a variety of systems modelling tools and is particularly strong in Systems Dynamics and Agent-based modelling. The website also contains many useful sample models and simulations. The cost is your model/simulation is available to Insight Maker.

To use Insight Maker  go to http://insightmaker.com/

The following is copied from the Insight Maker website. . .

At one level, you can use Insight Maker purely to map out conceptual models: using casual loop diagrams or rich pictures to describe a system. In this mode, Insight Maker functions as a powerful diagraming tool that lets you illustrate a model and then easily share it with others.

Once you have a model diagram created, you can start to add behavior to the different components using Insight Maker's simulation engine. Insight Maker supports two different modeling paradigms that together can describe most of the models you could imagine:

System Dynamics and Agent Based Modeling complement each other. In Insight Maker you can use either approach or integrate both of them together into one seamless model. To understand the pros and cons of an Agent Based Model versus a System Dynamics model, we can explore how these two techniques might approach the same problem: modeling the spread of an infectious disease in a population.