📝 Game Formats

Warning

Formats specifications are based on reverse-engineering and may contain inaccuracies.

🧊 Model Formats

.mcsa Scene Assets (MCSA.bt)

Configuration: Flags, Scales.

Geometry: Name, Material, Vertex positions, UV1, UV2, Normals, Tangents, Polygons.

Optional: Skeleton bones, Animation clips, Blend shapes.

.mcsb Scene Bundle (MCSA.bt)

Same structure as .mcsa with leading bytes prefix (?).

.mcvd Vector Dynamic (MCSA.bt)

Identical to .mcsa.

Used for low-poly geometry with animations (?).

.mcal Animation Library (MCAL.bt)

Character animation clips.

Used for retargeting animations between compatible armatures.

.efkmodel Effekseer Model (EFKMODEL.bt)

Geometry: Vertex positions, Normals, UV1, Polygons.

🧱 Texture Formats

.ol Object Layer (OL.bt)

Standard .dds (DirectDraw Surface) with simplified structure.

Mipmaps compressed with LZ4.

Some normal map textures are inverted.

Texture Suffix Conventions

Suffix	Map	Type	Purpose
_diff	Diffuse	Base Color	Raw surface color without lighting or reflections.
_spek	Specular	Reflectivity Control	Intensity and sharpness of highlights.
_nrm	Normal	Surface Detail	Simulates bumps and dents without changing geometry.
_emi	Emission	Self Illumination	Makes parts glow or emit light independently.

🖼️ Image Formats

.mic Media Image Container

Standard .png (Portable Network Graphics) with modified file signature.

Previously used for game GUI.

🗃️ TextureArray Formats

.texarr Texture Array (TEXARR.bt)

Container for .dds textures.

Textures referenced as group:path (e.g., probuilder:general/generic).

🗺 Region Formats

.mdat World Chunks Cache

Based on .mca (Minecraft Chunks Anvil) with extended world data.

Terrain chunks with blocks, metadata, lighting arrays and extra data.

Chunk data compressed with ZSTD.

Format is not fully documented.

⚙️ NBT Formats

NBT (Named Binary Tag) format, viewable with tools like NBT Explorer.

In game assets used GZIP or ZSTD compression.

Assets

Filename	Compression	Purpose
stalker/itemnames.dat	GZIP	Quest item descriptions.

Configs

Filename	Compression	Purpose	Keys (examples)
prefs	ZSTD	UI read state cache.	seenArticleLinks[], seenExperiences[], hasSeen*

Per-Character Configs

Located in /config/%CharacterName%/.

Files prefixed with sd (Synced Data) contain synchronized player state cached locally.

Filename	Compression	Purpose	Keys (examples)
common	ZSTD	General settings and UI states.	trashedItems[], caseLastOpenCount[], complaintsData{...}, seenFrontlineIntros
sd0	ZSTD	Incoming friend requests.	requests[]
sd1	ZSTD	Recent interactions (last 200 players).	interacts[{allianceId, type, username}]
sd2	ZSTD	Notifications history (last 100 popups).	notifications[{isRead, receivedMoment, notification{...}}]
sd3	ZSTD	Donate shop view history.	observedOffers[]
sd4	ZSTD	Profile customization UI state.	lastSeenBackgroundsVersion, lastSeenPatternsVersion, lastSeenStickersVersion, lastSeenTagsVersion

Config Formats

Filename	Format	Purpose
display	Text	Selected display ID.
keybindings	JSON	Keyboard control mappings.
options.json	JSON	Game settings (graphics, audio, gameplay).
quests.json	JSON	Quest visibility toggles.
waypoints.cfg	JSON	Custom map markers.

Other Formats

.xeon Encrypted Object Notation

Sensitive client data bundle. AES Encrypted.

Mirrors the assets folder structure.

.mcws World Slice

Chunk of a safezone. AES Encrypted.

Exact purpose is unknown.

Launcher Formats

.map Hash Mappings (HASHMAP.bt)

Hash Mapping (SHA-1) for game files.

Used by launcher to verify game assets integrity.

.torrent.bin Torrent Binary (TORRENT.bt)

Modified .torrent (Torrent) file.

Used by launcher for content delivery.

Trackers block unauthorized access (token required).