Traceability is recognized to be essential for supporting software development. However, a number of traceability issues are still open, such as link semantics formalization or traceability process models. Traceability methodologies underpinned by metamodels are a promising approach. However current metamodels still have serious limitations. Concerning methodologies in general, three hierarchical layered levels have been identified: metamodel, methodology and project. Metamodels do not often properly support this architecture, and that results in semantic problems at the time of specifying the methodology. Another reason is that they provide extensive predefined sets of types for describing project attributes, while these project attributes are domain specific and, sometimes, even project specific. This paper introduces two complementary modeling principles to overcome these limitations, i.e. the metamodeling three layer hierarchy, and power-type patterns modeling principles. Mechanisms to extend and refine traceability models are inherent to them. The paper shows that, when methodologies are developed from metamodels based on these two principles, the result is a methodology well fitted to project features. Links semantics is also improved