Computer generated "synthetic" biometrics are not widely used within the biometrics community beyond their current use as a research tool. Yet they offer a number of potential advantages that can be developed further to support the science and practical use of biometrics. Physics-based and intermediate-pattern generation of biometrics will require validation of the underlying statistical distributions if they are to be used as more than just a research tool. This paper proposes a taxonomy for physics-based models to be used in the creation of synthetic biometrics.