Systems Engineering – Cradle systems engineering software tool

Fundamental to a process and to these documents is a decision; to model or not to model.

Models are representations of a part of the system from a perspective that seek to allow that aspect of reality to be described succinctly and precisely. All systems exhibit the same three dimensions of behaviour, data and control. Many modelling notations exist (including ADARTS, UML, SysML, SASD, BPMN, IDEF, FFBD and others), each focused on these dimensions to different extents, each notation with its own background and intended use. There is no single correct, or best, modelling notation.

Models are not essential to SE, but are often a powerful means to describe relationships between the elements of the system. Processes that use models are said to follow a model based systems engineering (MBSE) approach.