  Any traditional engineering field has metrics to rigorously assess the
quality of their products. Engineers know that the output must satisfy the
requirements, must comply with the production and market rules, and must be
competitive.
  Professionals in the new field of software engineering started a few years
ago to define metrics to appraise their product: individual programs and
software systems. This concern motivates the need to assess not only the
outcome but also the process and tools employed in its development. In this
context, assessing the quality of programming languages is a legitimate
objective; in a similar way, it makes sense to be concerned with models and
modeling approaches, as more and more people start the software development
process by a modeling phase.
  In this paper we introduce and motivate the assessment of models quality in
the Software Development cycle. After the general discussion of this topic, we
focus the attention on the most popular modeling language -- the UML --
presenting metrics. Through a Case-Study, we present and explore two tools. To
conclude we identify what is still lacking in the tools side.
