We take here a broad view of model engineering as encompassing different approaches such as the OMG MDA™ proposal [9], the Microsoft Software Factories view [5], and many others. We distinguish the three levels of principles, standards and tools to facilitate the discussion. We propose the idea that there may exist a common set of principles that could be mapped to different implementation contexts through the help of common standards. We illustrate our claim with AMMA, a lightweight architectural style for a modelengineering platform that is currently mapped onto the Eclipse Modeling Framework [4].