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The Witcher 3: Wild Hunt (REDEngine v2) — Archive, Texture, String & Save Formats

Source: XeNTaX forum knowledge extraction (2015–2020). Covers .bundle/.cache archives, .xbm textures, .w3strings localization, .w3speech voices, .sav saves, meshes/skeletons, and tools.

1. Archives: .bundle and .cache​

Witcher 3 packs data in .bundle and .cache files.

Key Points​

FormatDescriptionExtraction
.bundleMain game archivesQuickBMS witcher3.bms (aluigi)
.cacheBulk textures (texture.cache)Not handled by witcher3.bms; use Lua-utils-for-Witcher-3
.mapArchive content map (v1.0.2)Shared by Haoose

Texture Cache Detail​

  • .xbm files contain only small preview images
  • Real textures live in content?\texture.cache
  • Initial .bundle repacking was not supported (requested feature)

2. Textures: .xbm → DDS​

.xbm files are CR2W containers (REDEngine format) wrapping DDS texture data without a DDS header.

XBM Structure (CR2W)​

CR2W magic → version → string table → CBitmapTexture fields:
 - width (Uint32)
 - height (Uint32)
 - compression (ETextureCompression = TCM_DXTNoAlpha)
 - textureGroup (CName, e.g., CharacterDiffuse)
 - residentMipIndex (Uint8)
 - textureCacheKey (Uint32)

Conversion​

  • Trick: Load DXT1 data without header (DDS without header), or strip .xbm header and add DDS one
  • Texture data is DDS-without-header; length/offset logic not fully documented

Extraction Tools​

Lua-utils-for-Witcher-3 (hhrhhr)​

lua unpack_textures.lua texture.cache output_dir
  • Requires Lua 5.3 + lua-zlib
  • 64-bit fix: use "<I4" instead of "<L" for 4-byte LE ints
  • Extracted files need DDS headers added via mod_dds_header.lua

witcher2_texture_converter (reused for W3)​

  • w2_xbm2dds.bms — .xbm → .dds
  • w2_dds2xbm.bms — .dds → .xbm
  • Includes nvcompress/nvdecompress

3. Localization: .w3strings​

W3 localization string files (new format vs W2 .w2strings).

Format​

  • Not simply XOR'd — contains "almost clean text (UTF16 with some html tags)"
  • Looks like XOR with a long byte sequence; fixed-key vs increment-key undetermined
  • Haoose released unpacker/repacker (zenhax t=964)

4. Voices: .w3speech​

Key Differences from W2​

  • Voice audio is NOT in .cache files — lives in enpc.w3speech files (per-language, e.g., enpc = English)
  • .w3speech format differs entirely from W2 .w2speech
  • W3 .w3speech tools are not the same as W2 .w2speech tools

5. Save Files (.sav)​

REDEngine save format.

Structure​

  • Single file split into 1,048,576-byte (0x100000) parts
  • Each part LZ4-compressed (LZ4 r131, default settings)
  • Header "checksum" = uncompressed file length in bytes
  • Decompressed payload resembles binary XML

Tools​

  • W3SavegameEditor (github.com/Atvaark/W3SavegameEditor) — unpacking support
  • W2 save references: Gibbed.RED, 13xforever's Witcher-2 SaveFormat
  • Editing breaks game easily

6. Meshes, Bones & Skeletons​

CR2W Mesh Files​

  • W3 meshes are CR2W files (like W2), lineage: .w2mesh → .w2mesh
  • W3 .w2mesh/.w2cutscene/.w2scene cannot be loaded by W2 REDkit — "Version 162 not supported" (max supported 115)
  • Faking version (0xA2 → 0x59/0x73) crashes REDkit

Bone Data (48 bytes/bone)​

  • ~48 bytes per bone: 16 bytes each for position/rotation/scale (32-bit floats)
  • Float values between -1 and 1 (tiny values like 2.0e-12) → need extra processing
  • Vertex data stored in half-floats needing division by 65535 + scale/offset
  • CSkeleton exposes bone names + parent indices; scale/offset (cookedData) on CMesh

Model Conversion Tools​

ToolNotes
Wolven-kitCDPR modding toolkit; github.com/Traderain/Wolven-kit; W3 + CP2077
RedTools (JLouis-B)Converts W3 + CP2077 models, source available
Witcher 3D Model ConverterCommon tool but no skeleton export
fmt_TW3_to_XPS.pyOld Noesis plugin (links dead)
AMD GPU PerfStudio / texture rippersTexture ripping; foliage "smudging" = alpha bleed-prevention

7. Official Modkit​

CD Projekt RED released Witcher 3 Modkit (mod support, announced 2015-08-14).

8. Tools Reference​

ToolPurposeNotes
QuickBMS + witcher3.bmsExtract .bundle filesaluigi; no .cache support
Lua-utils-for-Witcher-3Extract texture.cachehhrhhr; Lua 5.3 + lua-zlib
witcher2_texture_converter.xbm ⇄ .dds/.tgaw2_xbm2dds.bms, w2_dds2xbm.bms
Haoose .w3strings unpackerW3 localizationzenhax t=964
W3SavegameEditorSave unpack/editgithub.com/Atvaark/W3SavegameEditor
Wolven-kitCDPR modding toolkitW3 + CP2077
RedTools (JLouis-B)Model conversiongithub.com/JLouis-B/RedTools
Witcher 3 ModkitOfficial modding toolsCDPR, 2015-08-14
Witcher 3D Model ConverterModel conversionNo skeleton export

9. Community Resources​

ResourceWhat it isNotes
Modding.wiki — Witcher 3Community knowledge base (Nexus Mods)/users and /developers sections

Key Facts​

  • Archives: .bundle (extractable) + .cache (textures, need Lua tools)
  • Textures: .xbm = CR2W wrapper around DDS-without-header
  • Localization: .w3strings (UTF16 + obfuscation, not simple XOR)
  • Voices: .w3speech per-language (not in .cache, different from W2)
  • Saves: .sav = LZ4 1MB chunks → binary XML
  • Meshes: CR2W, version 162 (W2 REDkit max 115), bone parenting manual
  • Modding: Wolven-kit (modern), REDkit (legacy), Modkit (official)