Object Modeling Technique (OMT) is an object-oriented modeling and design approach developed by James Rambaugh. It uses three main models: the object model, which focuses on classes and objects; the dynamic model, which uses state diagrams; and the functional model, which represents processes and data flow using data flow diagrams. OMT proceeds through four phases: analysis, system design, object design, and implementation. Functional modeling in OMT defines the system's functions through data flow diagrams, which show processes, data flows, external actors, and internal data stores.