The presented hybrid environment represents a knowledge-based support of engineering computation. The knowledge-based subsystem is partially realized in Prolog, supporting an engineering software system written in a conventional programming language (typically in C). In an effort (i) to bring the latter component together with the Prolog-oriented subsystem, and (ii) to increase the intelligence of the environment, selected Prolog features are modelled in the environment of the chosen conventional programming language. The intrinsic intelligence of the environment can be increased particularly by registering whether or not variables are installed. This facilitates autonomous control of the computational process, providing not only a user-friendly environment, but also an active and predictive support of the user. Several practical applications were developed based on this concept.