Round-Based Time Model
A time model constructed of unmeasurable chunks of time, called turns, which are then grouped and/or clocked by rounds. Each actor typically takes one turn per round. The designer must further decide if turns within a round resolve sequentially, requiring an initiative system to impose order, or simultaneously.
Defining the round allows the game engine to attach behaviors to it (perhaps triggered at either the start of a round or at the end) and to measure time in terms of rounds (for buffs/debuffs). It also allows for mechanics like the intentions phase to have a place in the timeline to “live”.
Timing diagram for combat typical of a game like Wizardry or Bard’s Tale, featuring rounds, commands issued during the intentions phase, and sequential resolution via initiative.
This time model was nearly ubiquitous in the early days of computerized RPG and strategy games and is still popular today. Examples include CRPGs like the Wizardry series, Bard’s Tale series, and the (Heroes of) Might and Magic series, and TRPGs like Dungeons & Dragons.