1. A biometric recognition method, comprising: unobtrusively detecting and acquiring biometric data associated with a subject, wherein said subject is located and displayed on a floor of a three-dimensional building model, wherein a data-processing apparatus implements said three-dimensional building model; segmenting and extracting particular biometric features from said biometric data; comparing said particular biometric features to biometric data previously stored in a database in order to determine if said particular biometric features match said biometric data previously stored in said database and thereby rapidly and automatically determine if said subject comprises a repeat visitor; and automatically enrolling said particular biometric features acquired from said subject in said database if said particular biometric features do not match said biometric data previously stored in said database.