Despite the intense development in the applied computer hardware and software, optical designers made relatively small progress in creating new optical system types. This fact makes it important to develop new effective algorithms, especially for the first stages of the design process. In case of triplets or three components optical systems, corrected for finite or infinite object distance, at the beginning of the design process, the designer decides the constructional parameters (magnification, constructional length and image distance) based on the basic specifications. With these constructional parameters, the internal parameters (component focal lengths, air gaps) can be calculated as functions of the front and rear foci. It is also apparent that complex systems can be split to three components (or degraded three components, doublet or singlet) groups. Considering these facts, a procedure was developed for generating the corresponding component focal lengths and air gaps of any complex optical system, based on the targeted specification and optimisation values.