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Euro Truck Simulator 2 / American Truck Simulator (Prism3D Engine) — Archives, Models & Config

Source: XeNTaX forum knowledge extraction (2012–2023). Engine: Prism3D (SCS Software proprietary). Games: ETS2 (2012), ATS (2016), Scania Truck Driving Simulator.

1. Engine & Archive Overview​

AspectDetail
EnginePrism3D (SCS Software)
GamesETS2, ATS, Scania Sim
Archive (base).scs (SCS# container)
Archive (mods).scs (ZIP-based)
Config.sii (text, encrypted as .3nk/.3nK)
Encryption3nK header on locale.scs, def.scs, base_cfg.scs

Pipeline​

Game data → *.scs (SCS#) → extract → *.sii / *.pmg / *.pmd / *.mat / *.tobj / *.dds
Encrypted: *.3nk / *.3nK → decrypt → *.sii.txt

2. SCS Archive Format (.scs)​

Spec​

Magic: "SCS#" (4 bytes)
Version: uint32
Magic: "CITY" (4 bytes)
File count: uint32
Offset 0x1000: File table begins

Per file (24 bytes):
 uint32 HASH1
 uint32 HASH2
 uint32 OFFSET
 uint32 NULLS
 uint32 FLAG
 uint32 CRC
 uint32 SIZE (decompressed)
 uint32 ZSIZE (compressed)
Filename = "%08X%08X" % (HASH1, HASH2)
If SIZE == ZSIZE: stored; else: zlib compressed

Hash Algorithm​

  • Custom hash (long MASM32 function by Ekey)
  • Recovery: Unpack def.scs → search for paths in files (e.g., model_desc: "/model/sign/...")
  • Tool: SCSHasher (Ekey 0.1) — generates hashes from known paths
  • Community builds hash dictionaries from collected filenames

Encryption (.3nk / .3nK)​

  • Header: 3nK (little-endian)
  • Files: locale.scs, def.scs, base_cfg.scs contain encrypted .sii files
  • Tool: SCSSIITool (Ekey) — SCSSIITool <InFILE> <OutFILE>
  • Input: extracted file with 3nK header
  • Output: decrypted .sii (text) or .txt
  • QuickBMS: aluigi's scsgames.bms supports SCS# + ZIP + 3nK decryption
  • aluigi.org/papers/bms/scsgames.bms

Repacking​

ToolStatus
QuickBMS (aluigi)Script supports reimport — but encryption reimport fails
Ekey tests"Game don't work after reimport" (2013) — encryption callback issues
aluigi fixQuickBMS 0.5.17c fixed reimport bug — game still rejects reencrypted locale.scs
WorkaroundMod via loose files / overwrite in mod directory (SCS mod system)

Mod System​

  • Native: SCS games load .scs mods from mod/ folder (ZIP-based)
  • Priority: Mod archives override base game
  • Best practice: Package mods as .scs (ZIP) — no need to repack base game

3. SII Format (Text Config)​

Structure​

  • Custom text format (key-value, nested)
  • Extension: .sii (binary/encrypted) → .sii.txt (decrypted)
  • Example:
model_desc: "/model/sign/navigation/3hw_exit_far_d.pmd"
model_coll: "/model/sign/navigation/3hw_exit_far_d.pmc"

Editing​

  • Decrypt with SCSSIITool → edit text → re-encrypt (problematic)
  • Alternative: Create mod with modified .sii in loose file structure

4. Model Formats (Prism3D)​

File Types​

ExtensionDescription
.pmgModel geometry (Prism3D Model Geometry)
.pmdModel descriptor (references .pmg, .mat, .tobj)
.matMaterial definition
.tobjTexture object (references .dds)
.ddsTexture (DXT/BC compressed)
.pmcCollision mesh
.sklSkeleton (rare)

PMG Format (Geometry)​

  • Versions: 0x11, 0x13, 0x15 (ETS2/ATS Wyoming+)
  • Structure: Vertex buffers (pos, normal, uv, tangents), index buffer, submeshes
  • Vertex formats: Multiple (static, skinned, instanced)

Tools​

ToolAuthorNotes
SCS Blender ToolsSCS SoftwareOfficial — modding.scssoft.com/wiki/Documentation/Tools/Download
ConverterPIXWrappersimon50kedagithub.com/simon50keda/ConverterPIXWrapper — PMG/PIX → Blender
3D Object ConverterKarpativ10.001+ supports PMG 0x11/0x13/0x15 — 3doc.i3dconverter.com
NoesisDurik256 / SharppyScripts: fmt_pmg.py, fmt_euro_truck_sim_pmg.py
SCSArchivierCommunityExtract .scs archives

Batch Conversion Pipeline (Noesis)​

  1. Extract .scs → get .pmg, .pmd, .mat, .tobj, .dds
  2. Noesis script reads .pmd → finds .pmg + textures
  3. Batch export → OBJ/FBX/STL
  4. Sharppy's script (2022): fmt_euro_truck_sim_pmg.py — handles material/texture linking

5. Texture Formats​

DDS​

  • Format: Standard DDS with DXT1/BC1, DXT5/BC3, BC5, BC7
  • Mipmaps: Yes
  • Tools: Any DDS viewer, texconv, Paint.NET, GIMP

TOBJ (Texture Object)​

  • Format: Text (.tobj) or binary
  • Content: Texture path, wrap mode, filter, alpha test, etc.
  • Example:
texture: "/vehicle/truck/man_tgx/texture.dds"
wrap: repeat
filter: linear

6. Audio​

AspectDetail
EngineFMOD (legacy) / custom
Files.bank, .wem (Wwise?) — not extensively documented in threads
ToolsFMOD Studio, Wwise, vgmstream

7. Localization / Language Files​

Structure​

  • Encrypted: locale.scs → contains .3nk files
  • Decrypted: .sii text files with key-value strings
  • Languages: Each language = one .3nk file in locale.scs

Workflow​

  1. Extract locale.scs (QuickBMS scsgames.bms)
  2. Decrypt .3nk → .sii.txt (SCSSIITool)
  3. Edit text
  4. Problem: Re-encryption + repack breaks game
  5. Workaround: Use SCS mod system with loose .sii files

8. Key Repositories & Tools​

Tool / RepoAuthorPurpose
scsgames.bmsaluigiQuickBMS: SCS# + ZIP + 3nK decrypt
SCSSIIToolEkeyDecrypt 3nK → SII text
SCSHasherEkeyGenerate file hashes from paths
SCS Blender ToolsSCS SoftwareOfficial Blender import/export
ConverterPIXWrappersimon50kedaPMG/PIX → Blender (open source)
3D Object ConverterKarpatiCommercial: PMG 0x11/0x13/0x15 support
Noesis scriptsDurik256, SharppyBatch PMG → OBJ/FBX

9. Gaps / Unresolved​

  • 3nK re-encryption: No working tool to encrypt edited SII back to 3nK
  • SCS# repacking: QuickBMS reimport fails on encrypted archives
  • Hash algorithm: Not publicly documented (Ekey's MASM32 code only)
  • Skeleton/animation: .skl format not documented
  • PMG version 0x15+: Newer ATS versions may have updates
  • Material system: .mat format not fully documented

10. Cross-References​

  • Prism3D engine: Shared across ETS2, ATS, Bus Simulator, Scania Sim
  • SCS modding wiki: modding.scssoft.com — official documentation
  • QuickBMS: Universal extractor — scsgames.bms reusable
  • Blender SCS Tools: Official pipeline for asset creation
  • Noesis: Generic model viewer — scripts portable