Rational Software Modeler
Rational Software Modeler (RSM), made by IBM's Rational Software division, is a Unified Modeling Language (UML) 2.0-based visual modeling and design tool. Rational Software Modeler is based on the Eclipse open-source software framework and is used for visual modeling and model-driven development (MDD) with UML for creating applications and web services.
Source: Wikipedia — Rational Software Modeler (CC BY-SA 4.0)