This paper focuses on the development of the main component of Platform Independent Model (PIM) of Model Driven Architecture e.g. class diagram defined in Unified Modeling Language (UML), which has necessary details for transformation into Platform Specific Model (PSM). It is important to formulate core principles of development of well-structured class diagram at a conceptual level, using knowledge of the problem domain, which consists of two interrelated models of system aspects – business processes and concept presentation. Defini-tion of relationships of classes is important for PSM generation, therefore the re-search how it could be defined is performed. The hypothesis that it is possible to derive a class structure from initial business information is adduced. Information about the problem domain is presented in the form of two-hemisphere model that describes two interrelated parts of the most important aspects of a system, namely business process and concept models. These models serve as a source model for class diagram receiving. Capacity for the class diagram generation, based on the two-hemisphere model, is represented by a collection of graph transformations and illustrated with examples, where definition of different kinds of relationships (namely, aggregation, dependency, generalization) is displayed.