How to Trace Model Elements?

Motivation In model-driven engineering models enjoy the same status as customary source code. During the development process, many different versions or variants of models are created. Thereby, developers need to trace model elements between different versions to answer questions like Since when does element X exist in this model? or When did element Y disappear?. Regarding variants developers are often interested if certain elements or groups of elements (e.g. containing a bug) also exist in other variants. Questions from the analytical point of view, such as logical coupling, require traceability of model elements, too. Traceability of elements becomes a challenge, since in daily practice, models are often stored as textual files, e.g. XMI, in versioning systems such as CVS or SVN. However, these systems are not aware of models, i.e. syntax and semantics inside the textual files. Subsequently, we present an approach for fine-grained element tracing based on difference computation. We furthermore offer a model-independent visualization of our trace information.