Towards the systematic design of model animation: key ingredients and general guidelines

Model Animation (MA) is a practical technique for providing modellers and Model Transformation designers an insurance that their models behave as expected. This is specially relevant in expertise domains where models have a natural visual representation, i.e. a dedicated concrete syntax. MA can be seen as the visual representation of Model Transformation simulation. It supports Model Transformation designers understand, trace, monitor, and ultimately debug their specification using visual clues. In contrast to other techniques surrounding Model-Driven Engineering, MA has received less attention, in contrast to, e.g. testing or debugging. This paper is a first step towards the systematic engineering of model animators. It identifies three key challenges: (i) how to effectively, explicitly and precisely define the concrete syntax to enable MA; (ii) how to build an MA language to express animations units in a compositional way, so that animations become flexible in their definition, and reusable across several Dsls; and finally (iii) how to explicitly relate MA units with their transformation counterparts, to avoid reimplementing the transformation scheduling. We analyse these challenges to extract some requirements for future animators, and give a partial conceptual proposal that fulfil them, paving the way towards the creation of a family of animation tools that would work alongside transformation engines. We then show, on simple examples, how these propositions apply and to which extent they promote flexibility and reuse.