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

core loop

build a home or download one from the Gallery -> moodlets from events and surroundings set the dominant emotion -> emotion unlocks interactions and speeds skills -> pursue aspiration milestones and a career -> earn rewards -> share households and builds

design notes

The Sims 4 makes emotion the central state: moodlets from actions, events, objects, and social interactions carry an emotion type and weight, and the strongest set the Sim's single dominant emotion, which gates emotional interactions and speeds matching skills. Adult personality is three traits plus a bonus trait from the chosen aspiration, and completing aspiration milestones grants reward traits. Build mode treats rooms as units that can be moved, duplicated, saved to a library, and shared through the Gallery; the base game became free to play on 2022-10-18. Neighborhood Stories, a free update that advances unplayed households, is the offscreen-life-progression mechanic.

relations

21 stored edges
influenced by
uses

Memories and thoughts

Moodlets carry an emotion type (such as Happy, Focused, Flirty, Angry, Tense, or Sad), an intensity, and a timer; the highest-weighted emotion becomes the Sim's dominant emotion.

core
uses

Needs decay

Six needs (Hunger, Bladder, Energy, Social, Hygiene, Fun) decay and spawn negative moodlets such as Hungry or Bored when low.

core
uses

Personality traits

Adults hold three traits and children and teens two, plus one bonus trait from the aspiration; traits add moodlets, autonomous behaviors, and exclusive interactions.

core
uses
supporting
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Aspirations and wants

The chosen aspiration grants a bonus trait and a track of milestones whose completion earns reward traits; short-term whims, later reworked as wants and fears, appear from emotions and traits.

supporting
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Autonomy levels

Free will can be toggled; with it off Sims act only on player orders except for urgent needs.

supporting
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Blueprints

Sims, households, rooms, and lots can be saved to a personal library and placed again.

supporting
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Career ladder

Careers require related skills, for example Cooking and Mixology for Culinary.

supporting
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Content sharing

The Gallery uploads and downloads Sims, households, rooms, and buildings from other players inside the game.

supporting
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Building placement

Build mode draws walls and rooms, places premade rooms, and moves or duplicates whole rooms.

supporting
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Lifecycle and aging

Newborn, infant, toddler, child, teen, young adult, adult, and elder; toddlers were added in 2017 and newborn and infant in 2023.

supporting
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Modding API

Python script mods and package files load from the Mods folder.

supporting
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Mood and breakdowns

Dominant emotions unlock emotion-specific interactions and raise gain for matching skills (Inspired for creative, Focused for mental, Energized for physical); extreme states such as Hysterical can kill.

supporting
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Off-screen life progression

Neighborhood Stories, added in a free update, advances unplayed households with events such as moves, relationships, and births, with settings that limit which households and event types it may touch.

supporting
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Relationship values

Separate friendship and romance bars per pair.

supporting
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supporting
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Smart objects

Objects advertise need, skill, and emotion gains, and Sims multitask, such as talking while cooking.

supporting
uses

Social exchanges

Social menus are filtered by emotion and traits, with emotion-specific variants of interactions.

supporting

backlinks

computed from other records

sources

2
Wikipedia contributors (2026). The Sims 4. Wikipedia
The Sims Wiki contributors (2026). Motive. The Sims Wiki (Fandom)

provenance

runs in log/runs
2026-10-24
created2026-10-24-catalog-gccatalog
2026-10-24
reviewed2026-10-24-review-fixesmaintenance
2026-10-25
reviewed2026-10-25-contributor-readinessmaintenance