The modelling of complex developing systems of a natural, technical and social character (for example, city space) in the modern-day context is determined based on the principles of synergetics. It is therefore important to clearly understand the methodological foundations and technologies of such modelling. Synergetics describes the mechanism of self-organisation of complex systems in the condition of their instability. This makes it essential to define the factors and conditions that identify transients (including in architectural and town-planning formations): bifurcation points and possible fluctuations, probable scenarios of development, and cascade rhythm parameters that determine the pace characteristics. Also, noteworthy is the potential of information (computer) support for research, analysis and modelling of complex systems.