The maturity of Model Driven Engineering facilitates the development of domain specific languages. The creation of the languages relies on the definition of metamodels, but also on their corresponding visual notations. But one can wonder what is the quality of a new language. It can result in inunderstandable diagrams with inappropriate notations. Then our goal is to evaluate the quality of metamodels and notations by metrics, which are integrated in a modeling environment named ModX. In this manner, ModX allows designers to calculate pre-defined metrics, but also to create new ones. We show the interest of this approach by propos- ing, into ModX, metrics about notations'quality (aspect of- ten neglected in the model-driven-engineering domain).