The Prototype Builder is a planner-friendly Return on Investment (ROI) model similar to the models developers use to evaluation the financial feasibility of potential projects. The Prototype Builder is an intergral part of the Envision Tomorrow scenario planning process. The tool is used to create the building library used in scenario painting, but also has significant utility as a stand-alone tool.

As a stand-alone tool, the Prototype Builder is used to analyze the market feasibility of building types. It helps planners determine whether zoning and development codes will actually result in desired development outcomes given current and future market conditions. It can also be used to identify how various policy changes affect building type feasibility and how much funding may be needed to make desired development types “pencil out.” This can include direct subsidies for individual projects as well investments in public amenities that tend to increase average rents in a community and open up new development opportunities.