Foam models can reveal ergonomic flaws in the design that cannot be detected in CAD, as well as giving you a realistic preview of the scale of your designs. Several concepts can be made and evaluated very quickly, sometimes in just a few hours. During the evaluation process, changes can be made to the model and incorporated into the design. The quick, iterative process of foam models can save thousands of dollars in development and reduce time to market.
Urethane foam board is available in varying densities from hard to soft, but usually a low-density foam is desirable to make the model quickly and easily. A foam model can be made by hand from a napkin sketch or CNC machined from CAD data.