Discrete event simulation (DES) is a modeling technique used to understand how a system operates over time by representing it as a sequence of individual, discrete events. Rather than viewing a process as a smooth, continuous flow, discrete event simulation focuses on specific moments when something changes—such as an arrival, a transfer, or the completion of a task.
This approach is highly flexible. Discrete event simulation can be applied to simple, contained systems or expanded to model complex operations involving many interacting elements, depending on the scope of the analysis. Systems evolve through distinct moments in time, not continuously, and each event represents a change in the state of the system.
In practical terms, discrete event simulation allows organizations to model how work progresses through a system. For example, a part entering a process, being worked on, and exiting as a finished item are all treated as separate events. Time within a simulation often represents durations or intervals—such as how long an operation takes or how demand fluctuates—making it possible to analyze throughput, bottlenecks, and idle time.
Every discrete event simulation is built around three foundational elements: entities, events, and resources. Entities are the objects moving through the system, such as parts, products, or customers. Events are moments when something happens to an entity, including arrival, processing, storage, or departure. Resources are the people, equipment, or systems required to perform work, such as operators, machines, or material-handling equipment.
FlexSim™ is a powerful discrete event simulation platform designed to help organizations model, analyze, and improve real-world systems. By using FlexSim, teams can build digital representations of manufacturing lines, warehouses, logistics networks, or service operations and test how changes to resources, layouts, or process logic impact overall performance before implementing them in the real world.
Discrete event simulation is not used simply to visualize a process. It is a decision-support tool that enables organizations to explore what-if scenarios—such as adding capacity, changing staffing levels, or modifying layouts—before committing time or capital. Tools like FlexSim help reduce risk, support data-driven decisions, and improve operational planning.
This article introduces the fundamentals of discrete event simulation and how tools like FlexSim are used to analyze real-world systems. To explore more detailed examples, see simulation in action, and gain deeper insight into operational modeling, watch the full webcast.