Substitution of Alternatives

The Urban Simulator project is not just about simulation software. It is a methodology integrating existing systems such as CAD (computer-aided design) and GIS (Geographic Information System) with visual simulation. As such it enables the modeling, display and evaluation of many alternative environments:

• Neighborhoods as they currently exist
• Neighborhoods after new building and/or new
• highway construction
• Entirely new developments
• Historic reconstruction

The close integration of the Urban Simulator with the UST modeling and database methodologies has resulted in a system which is both powerful and easy to use. For instance, modelers can insert a simple command such as "switch oak elm pine palm" in the attribute field of any node in the scene graph (we might name this node "tree"). As the database is loaded the attribute field for this node will be evaluated and an entry made in the "Modify" Menu called "tree" (after the node name). Under the category "tree" there would be four items ("Alternatives"), namely "oak", "elm", "pine", and "palm". The model would initially appear with the oak visible (because it was listed first), but selecting any of the alternative entries (e.g. "palm") causes that model to be dynamically substituted for the oak tree. Likewise, multiple alternatives for roads, bridges and new construction can be interactively evaluated.