SYNTHESIS is a tool-making expert system (TMES) that ensures building of hybrid expert system shells (HESS). The latter, when being filled in with knowledge and data, allow to solve problems of research design of technical objects. The research design is aimed at creating of conceptual decision of a technical object (technical object's image). In the frame of SINTEZ family's HESS, this problem is solved in two stages: specification of well grounded requirements to the object under design; synthesis of the object's image on the basis of specified requirements. The HESS allows the user to create alternative variants of the image of technical object, to calculate values of the characteristics of various variants using the solver and to find the best variant on the basis of multicriteria analysis and logical inference.