File Types

^{_{A reference list compiled by Amethyst Lilac}}

While you create and look around the game’s files, you’ll come across many different files. Here’s a brief (in most cases, very brief) description of some.

Some may contain speculation or be vague, and may be updated later with more information.

In different circumstances, a file with a multi-word name may have spaces omitted or included (DevelopmentalMilestones or Developmental Milestones). If the only difference is spacing, they are nearly always the same file type. On this page, spaces are used for readability.

File Extensions

These are files that you will primarily see/edit/create as a final product. These are the files that you install somewhere (or the game does).

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.package

A .package file (commonly called a package or package file) is a Maxis proprietary file format. It’s used both for mods and game files. It can contain a single file or many files, such as tuning files, images, and strings. The game reads the files contained in the package file, and assuming they’re created and used correctly, will use the contents in game.

Package files are used by modders for things such as tuning mods, custom content, UI mods, string overrides, etc. Most mods contain one or more package files. They are the most commonly used file format for mods.

Package files are used in game files in the user data folder in Documents (localthumbcache.package and accountDataDB.package, for example) and in the game’s installed files (ClientDeltaBuild0.package, magalog.package, etc.).

.ts4script

A .ts4script file (commonly called a script or a script file) is a renamed .zip (compressed folder) file. They contain python script mods, most commonly in compiled .pyc files.

Script mods interact with the game’s python coding, allowing them to do things that mods that have tuning files only can’t do, including injecting tuning so that multiple tuning mods can co-exist without overriding the same things and adding new things that don’t exist in the game, such as new classes, or altering the way scripted parts of the game work.

Most mods don’t require a script, but there are some things that can’t be done without one. Most, but not all, script mods (mods that have a script file) also have one or more package file.

.blueprint, .bpi, .hhi, .householdbinary, .rmi, .room, .sgi, .trayitem

These are files that are typically found in the tray folder. Any tray item (a household, room, or lot) will be made up of multiple of these. Which ones are involved for a particular tray item varies.

Blueprint (.blueprint; lot information) and Blueprint Image (.bpi; a lot’s thumbnails) are related to lots. .hhi and .householdbinary are related to households. .rmi and .room are related to rooms. .trayitem files are used by all three.

One example of when these files may be used in modding is in creating household overrides for premade sims, or creating sims to spawn in game for a mod.

.cfg, .json

These are settings files. They are used in game files, and may also be included with or created by mods that contain script files.

.ini

These are settings files, and are typically used in game files, both in the user data folder in documents and in the game’s installed files.

One example of when you may be working with these files is if you’re working with the game’s camera settings.

.log

These are log files, usually created by a mod that contains a script file.

.RAR, .7z, .zip

These are compressed folders that contain useful files, and the contents are usually extracted before using them.

.ts4script files are renamed .zip folders.

Mods and custom content are often uploaded in compressed folders of one sort or another.

.save, .ver0, .ver1, .ver2, .ver3, .ver4

These are files that are found in the saves folder in the user data folder in documents. They are the save files, with up to five backups per save slot (.ver0 to .ver4). Renamed .package files.

.txt

These are plain text files. They may be used by the game or created by mods that contain script files.

.world

These are files that determine what a world looks and acts like in game.

One example of when a .world file is used in modding would be certain kinds of lighting overrides.

Internal Files

These are files that are primarily used inside another file, such as a package or a script file. They are typically not used as an end product.

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Script Mod Files

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.py

An uncompiled python file. Python files are used in script mods, but are usually compiled and placed in a .ts4script file before use.

.pyc

A compiled python file. Python files are used in script mods, and are usually compiled and placed in a .ts4script file for use.

General Files in Packages

Uncategorized or in multiple categories.

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Age Gender Map

A table that maps the age and gender variants of sculpts and modifiers.

Example:

CTYAE/F    yfheadBody_Heavy
CTYAE/M    ymheadBody_Heavy
P/U        puheadBody_Heavy
I/U        iuheadBody_Heavy
BaseName   Body_Heavy

When changing a Sim’s age or gender in CAS or in game, this will be used to lookup the correct variant of the modifier or sculpt (if needed). The game loads these mappings with hard-coded instance numbers, so you cannot add a new AgeGenderMap, but you can override an existing one and add mappings to it.

Combined Binary Tuning

How the game stores and uses tuning, as combined files instead of loose tuning files.

DST Image

May be icons, object diffuse images, normal or specular maps, or various other game images.

Generic MTX

Likely related to requiring a pack for something that shows up if you don’t own that pack (date activities, for example).

Light

Information about where and how light is used. Used in actual build/buy mode lights, but also other places.

Magalog

A file that contains information about sets of objects. This may be build/buy items, such as a table that places with chairs pre-attached, or it may be things like a room.

Magazine Collection

A file that contains information about pre-built rooms.

Object Modifiers

A list of modifiers to objects (including sims), such as surfaces, what’s being carried, shoe type, terrain type, etc.

Path

Routing information.

PNG Image

Mainly used in magalog files, but also used for some background images and random other images.

Record Bundle

Collections of files bundled together. At present, there are four: two collections of Clip Headers, one of Object Definitions and Slots, and one of Lights and Footprints.

Rig

The parts of something, which other things can attach to or affect. The collection of Bones.

S4S Merged Package Manifest

A file created by Sims 4 Studio and included in a package file when multiple package files are merged into one, listing all of the original packages and their contents. This file is essential if the package ever needs to be un-merged.

Sim Data (in a package file)

SimData is a file that is usually paired with a tuning file. It is required by many different tuning types but not all. When it is paired with a tuning type, it’s not optional, and any elements that it has in common with the tuning file must match to prevent mysteriously unintended behaviour. Occasionally, there may be a SimData file that is not paired with a tuning file, or two SimDatas for one tuning file, but those cases are rare.

An example of when SimData is used is in a Buff. The UI reads the SimData to know what to display to the player, because it doesn’t have access to the tuning, and the simulation reads the tuning to know what effects the buff has.

Sim Info

Information about premade sims, preset outfits and uniforms, and mannequins.

String Table

String Tables are files made up of stings, which are bits of text. They hold the text you see in game.

Tuning Files

Tuning files are written in XML (Extensible Markup Language).

There are multiple ways to divide tuning files up. Module is used here.

There are many different tuning files. Not all are listed here.

Important note: if your tuning is malformed, you will be unable to save your package. You must correct the issue before you will be able to save.

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Animations

Animation Element, Object Animation Element

Used to ask for an animation to be used, with what object, and how to end it, sometimes with other information.

Animation Element Set

A set of Animation Elements which may be used depending on posture for the same or similar interaction.

Object Pose

A static animation (a pose).

Aspirations

Aspiration

A file that contains one or more objectives to be completed. May be a single objective with no other information, or may be a full aspiration level.

Aspiration Assignment

A version of an Aspiration for a career assignment.

Aspiration Career

A version of an Aspiration for a career goal.

Aspiration Category

A category for one or more aspirations.

Aspiration Familial Trigger

An aspiration that notifies someone else when a sim completes it, such as ‘Have Sim’s child max out any of the child skills!’

Aspiration Gig

An aspiration for a career gig.

Aspiration Notification

Currently, notifications sent situationally based on traits, such as an infant having low motives.

Aspiration Organization Task

Tracks progress in organizations, currently just for university.

Aspiration Sim Info Panel

Tracks sim stats, such as number of bathroom breaks.

Aspiration Track

The unifying file for an aspiration, listing the aspiration levels, whimset, primary trait, and UI data for the aspiration.

Aspiration Unfinished Business

Tracks the bucket list.

Timed Aspiration

An aspiration that expires with time, such as a resolution.

Away Actions

Away Action

Something a sim can do while not on the active lot, such as filling a need.

Balloons

Balloon Category

Tuning for thought and speech balloons.

Braodcasters

Broadcaster

Affects sims within the defined constraint relative to whatever has the broadcaster.

Buffs

Buff

Buffs, or moodlets, may be the visible buffs you see in game or invisible buffs. If they are visible, they’re the squares that you see under a sim’s portrait in the bottom left. Visible buffs usually affect mood and have descriptive text. Invisible buffs are often used to control what a sim gains or loses from a trait or situation.

Burnout Buff

Buff added during burnout.

Business

Business

Data about a business type.

Business Rule

Residential Rental apartment rule.

Careers

Career Tone

Away Actions that can be chosen for a sim to do while at school or work (non-active).

Clubs

Broadcaster Club Rule

A broadcaster that affects how sims react to club members following/breaking the club rules.

Delivery

Scheduled Delivery Loot

Scheduling a reward to arrive in the mail.

Live Drag

Live Drag Loot Actions

The result of live dragging an object.

Interactions

Loot Actions

A list of loots (things caused by something else).

Random Weighted Loot

A list of loots that may get applied randomly with options for weighting the loot chosen.

Weighted Single Sim Loot Actions

Loots that get added to a sim in a situation.

Situations

Situation Goal Loot Actions

A list of loots to add to participants if the situation’s goal is completed successfully.

Whims

Aspiration Whim Set

Tracks whim sets.

Objectiveless Whim Set

A whim set without specific objectives.

Custom Content

CAS Files

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Blend Geometry

Used in some CAS presets.

Body Part Thumbnail

Thumbnail for a preset (body shape, nose shape, jaw shape, etc.) in CAS.

CAS Part

Contains various flags (telling the game when it can be used and by who, among other information) and other details about a CAS item.

CAS Part Thumbnail

Thumbnail for a CAS item.

CAS Preset

A CAS preset — eye shape, nose shape, body shape, etc.

Deformer Map

Used in body and body part shape customization (slider use). Uses UV1 in blender.

Geometry

Contains information about the physical properties of a CAS item.

LRLE Image

Images used as the diffuse map for a CAS item.

Pelt Brush

Brushes used for painting in CAS.

Pelt Layer

Layers, patterns, and stencils for paintable items in CAS.

Pet Breed Coat Pattern Thumbnail

Thumbnails shown in CAS for pet breeds, werewolf coats, and fairy wings (paintable CAS items).

Pet Coat Pattern

Pattern information for pet breeds, werewolf coats, and fairy wings (paintable CAS items).

Pet Face Preset Thumbnail

Thumbnails shown in CAS of pets (presumably of their heads, but shows in the files as full bodies).

Region Map

Grouped information about a CAS item’s LODs.

RLE 2 Image

Images for certain CAS items. Diffuse maps for items that do not use colour sliders, and shadow maps.

RLES Image

Specular maps for CAS items.

Sculpt

A body part shape, a CAS preset.

Sim Featured Outfit Thumbnail

Thumbnail for a styled look.

Sim Hotspot Control

Controls the location a slider connects to a sim in CAS.

Sim Modifier

CAS presets.

Sim Preset

Sim presets in CAS — the ones that change the look of the entire sim, selected by the head for human/occult sims, and by breed for animals.

Sim Preset Thumbnail

Thumbnails for sim presets in CAS — the ones that change the look of the entire sim, selected by the head for human/occult sims, and by breed for animals.

Skintone

Skintones. One per swatch.

Styled Look

A styled look.

Walkstyle

Details of a walkstyle, similar to a Locomotion Builder.

Build/Buy Files

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Block

Build tools, such as Basement Tool, Custom Pool Tool, and L-Shaped Deck.

Buy Build Thumbnail

Thumbnail for a Build/Buy item.

Column, Fence, Floor, Floor Trim, Foundation, Fountain Trim, Frieze, Half Wall, Half Wall Trim, Ladder, Platform, Pool Trim, Railing, Roof, Roof Pattern, Roof Trim, Spandrel, Stairs, Terrain Paint, Wall, Wall Trim

A file for the specific object mentioned, one per swatch.

Cutout Info Table, Model Cutout

When an object cuts out part of another (a door or window in a wall, a sink in a counter), this tells the game what size and shape of hole to remove.

Also used in generating thumbnails.

Deco Trim

A file for Seasons exterior holiday decorations (banners, bunting, garlands, etc.), one per swatch. A hidden item.

Footprint

The shape and size or an object, along with various related properties. Usually controls part of where an object can be placed, how close it can be to other objects, and how close sims can get to the object (including if they can walk on/through it).

Material Definition

Information about the material/surface of walls and floors.

Material Set

Appears to be sets of Material Definitions.

Model, Model LOD

Contains information about the physical properties of a Build/Buy item.

Object Catalog

Contains information about a specific swatch of a build/buy item, such as tags and flags.

Object Catalog Set

The Object Catalog for a set of items that place from the catalogue together.

Object Definition

Contains information about a specific swatch of a build/buy item, such as components, linked footprint, and tuning used.

Pond

Pond tools (raise, lower, or remove water; fill to height).

Slot

A place designated to be where another object can be placed, whether in build mode, live mode, or through tuning such as FX.

Style

Style tags for Build/Buy mode.

Terrain Tool

Terrain tools: raise/lower/smooth/flatten terrain, flatten to height, and flatten lot.

Thumbnail Extra 1

Related to catalogue thumbnails framing.

Animation/Poses

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Animation State Machine (ASM)

Information about an animation.

Clip, Clip Header

An animation.

Locomotion Builder

Puts animations in sequence and determines things like the overall duration.

Locomotion Config

A list of walkstyles (all of them, including things like stairs, turning, horses while being rode and riderless, etc.).

Timeline Events

Appears to be things that happen while an animation plays, like sounds.

Audio and Video Files

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Ambience

Related to background noise.

AVI

Video files. NOT regular .avi files, but an odd format used by the game.

Sound Mix Properties

Sound configuration files.

Household Related

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Household Template

A template file for a premade household that will appear in a new game or when spawned by the game or a mod.

Sim Household Thumbnail

Thumbnails for premade households.

Save Files

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Memorial Thumbnail

Thumbnail of a sim who died in the save.

Save Game Custom Texture

Pictures and paintings from the save file.

Save Game Data

Data about the save at the exact time it was saved. Contains many things, including info to identify the save point and which save chronology it’s from, the account it was made on, the time it was made, what was on the notification wall, clubs, game options, custom colours from colour sliders to be shown in CAS, camera position, calendar info, sims… virtually everything that can be tracked as data.

Save Game Household Thumbnail

The household thumbnail for the last played household, as appears on the main menu.

Save Game Lot Level Thumbnail

Thumbnail for a premade apartment in the save that uses the plex system (at present City Living, Eco Lifestyle, and For Rent apartments).

Save Game Lot Travel Thumbnail Mask

Images that reflect which parts of a building are visible and which are hidden for apartments in the save that use the plex system (at present City Living, Eco Lifestyle, and For Rent apartments).

Save Game Lot Thumbnail 1

Main thumbnails for lots that have been viewed in the save.

Save Game Lot Thumbnail 2

Small thumbnails for lots that have been viewed in the save.

Zone Object Data

Information about lots in the save, listed by world and current lot name.

UI Files

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Credits

As it says, the credits — the people who made the game.

Cursor

Shockingly, these are the cursors the game uses.

Font Configuration

Various files to display text somewhere in game, such as I have read and accept the User Agreement and EA's Privacy and Cookie Policy., the Privacy and Cookie Policy itself, and button text, along with font and display configuration files.

Scale Form GFX

User Interface (UI) files.

World Files and Related

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Color Timeline Data

Appears to be related to world lighting.

Household Description

The name displayed in game for a lot.

Lot Description

Information about a lot.

Lot Preview Thumbnail

The pre-set thumbnails for lots.

Lot Type Event Map

Appears to be a list of walkby groups that are valid for certain basegame venue types.

Plex Thumbnail

Thumbnails for premade apartments using the plex system (at present City Living, Eco Lifestyle, and For Rent apartments).

Plex Unit Mask Thumbnail

Images that reflect which parts of a building are visible and which are hidden for premade apartments that use the plex system (at present City Living, Eco Lifestyle, and For Rent apartments).

Region Description

World descriptions.

Sky Box Texture Data

Which texture is used where and when for which world’s sky.

Spawner

Where a sim or object (such as a collectable) spawns.

Terrain Data

Appears to be which terrain textures are used in which region of which world.

Terrain Height Map

Appears to be heat maps of terrain height in the regions of the worlds.

Terrain Mesh

Terrain meshes, multiple per region.

World Description

Neighbourhood descriptions.

World Lot Architecture (WLA)

List of build items on a lot (walls, roofs, etc.).

World Lot Objects (WLO)

List of all objects on a lot.

World Map

Description of a world map, including camera position and lot dimensions.

World Spawner Info

Locations of sim spawners in neighbourhoods.

World Timeline Colour

World lighting colour based on time of day.

World Visual Effects Info

Info about visual effect spawner placement in the world.

Worldmap Lot Thumbnail

Default lot thumbnails.

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Originally written by Amethyst Lilac for this site.