Operational event-trace products consist of an event-trace diagram and an accompanying description that defines the particular scenario or situation. You model operational event-trace diagrams with IDEF3 diagrams to show interactions in terms of messages, or information transfers, between operational nodes arranged in time sequence.

The operational event-trace description can be used by itself or in conjunction with an operational state transition description to describe dynamic behavior of processes.

The event-trace diagram shows operational nodes involved in the scenario by vertical dashed lines, called operational node timelines. Horizontal line symbols between the operational node timelines represent the messages or Operational Events passed between the operational nodes. The operational events are drawn chronologically from the top of the diagram to the bottom; the horizontal placing or spacing of objects is arbitrary.

When operational event symbols are added to a sequence diagram they must be attached to the vertical dotted line representing an operational node. They will be placed horizontally as simple messages.