Abstract: A modeling system for modeling a process or system comprising a processor arranged to execute a user-interface module and to receive input commands from a user, wherein the user-interface module facilitates the building of a model from the input commands, wherein the model includes: (i) a plurality of hierarchical functions, wherein each function comprises one or more elements, wherein each function represents part of the process or system, and wherein each element is reproducible in more than one function, and (ii) one or more sequence-indicating links between functions that indicate a flow between the functions comprising the process or system, wherein the processor is arranged to control a display device to display the model to the user, wherein the modeling system is arranged to store data indicative of the model on a storage device; and wherein the modeling system is arranged to generate and output a document based on the model.