one dataset · paper, tables, graph, wiki
simgrammar the grammar of simulation

core loop

choose a character and episode -> practices offer actions for the situation -> player acts or waits -> other agents simulate each option and take the best for their desires -> emotions, evaluations, and relationships update -> the episode reaches an outcome

design notes

Richard Evans and Emily Short built Versu around social practices: recurring situations such as a meal or a conversation written as reactive joint plans that offer actions to participants without controlling them. Each agent tests a candidate action by applying it to the world state, scoring the result against its desires (over 300 in total), and undoing it, which the authors contrast with the estimated consequences used in The Sims. World state is a set of exclusion-logic sentences, and the Praxis language with a stress tester that runs hundreds of simulated instances supported over 1,000 parameterized actions. Linden Lab cancelled the project in early 2014; social practices have no mechanic id and are proposed as social-practices.

relations

6 stored edges
uses

Social exchanges

Social practices such as a dinner party or a conversation offer role-specific actions with preconditions, and most actions change how characters regard each other.

core
uses

Utility action selection

Agents score each available action by executing it on the world state, evaluating the result against their desires, and undoing it; the best-scoring action is taken.

core
uses

Memories and thoughts

Fine-grained emotions on Ekman's typology record their target and cause.

supporting
uses

Personality traits

Character files assign each agent desires that weight its action scoring.

supporting
uses

Relationship values

Agents hold evaluations of each other on roles such as attractiveness or breeding, which actions raise or lower.

supporting
uses

Storyteller director

A drama manager agent can act to push an episode's authored plot.

supporting

sources

3
Richard Evans, Emily Short (2014). Versu: A Simulationist Storytelling System. IEEE Transactions on Computational Intelligence and AI in Games 6(2)
Emily Short (2013-02-14). Introducing Versu. Emily Short's Interactive Storytelling
IFWiki contributors (2026). Versu. IFWiki

provenance

runs in log/runs
2026-10-24
created2026-10-24-catalog-gccatalog