Abstract: The present invention relates to a process for manipulating data models for the transfer of models between a plurality of software engineering tools (Ta, Tb, Tc, Td, etc.) and for the application of transformation rules to a model, wherein the transformation of data models is carried out by means of gateways (Ba, Bb, Bc, Bd, etc.) which make it possible to convert the format of one tool to the format of another tool by passing through a unique neutral intermediate format (NIM). The present process is remarkable in that the development of the gateways, in accordance with the so-called object-oriented approach, is carried out in an executed language, the gateways being executables which allow the transformation of a data model in several steps activated successively, in a systematic or conditional way, by means of a command language which describes a logic for dynamic concatenation of the steps, concatenation being a named, parameterized procedure.