Software engineering techniques made it possible for developers to build larger, and more accurate, reliable, and maintainable software-intensive systems. This was essentially possible by introducing techniques for raising the level of abstraction for describing the problem and its solution, and by clearly establishing a methodology to define both the problem and how to move to its solution. Model Driven Engineering (MDE) targets precisely at organizing such levels of abstraction and methodologies. It encourages developers to use models to describe both the problem and its solution at different levels of abstraction, and provides a framework for methodologists to define what model to use at a given moment (i.e., at a given level of abstraction), and how to lower the level of abstraction by defining the relationship between the participating models. Such an MDE process is supposed to be defined by means of assets, and methodologists have the duty to provide such assets. However, it is not yet clear what exactly these assets are, despite the fact that techniques to express them have already been widely studied. This position paper addresses this issue by identifying some of the MDE assets that have to be provided, and shows how they should be defined in order to enable them to participate in different MDE process definitions.