ImHex Patterns for Van Buren (Jefferson Engine)

This repository contains ImHex pattern files for the proprietary file formats used in Fallout: Van Buren (also known as Project Jefferson), the cancelled Fallout 3 by Black Isle Studios.

Overview

Van Buren uses a set of custom binary formats for 3D models, maps, creatures, items, GUI screens, archives, and more. These patterns document the structure of those files based on reverse-engineering work.

Pattern Inventory

Archive / Resource Layer

Pattern	File	Description	Status
chunk.pat	—	Reusable chunk header (tag[4] + version + size) and string helpers	New
grp.pat	.grp	Group archive (header + lump table + raw data)	Updated
rht.pat	resource.rht	Resource hash table (catalog linking names → .grp lumps)	Updated
stf.pat	.stf	String table (localized text)	Updated

Text / Config

Pattern	File	Description	Status
psf.pat	.psf	Sound configuration text (UTF-8)	New
gsf.pat	.gsf	Text file (UTF-8)	New
gls.pat	.gls	Group list text (UTF-8)	New
sco.pat	.sco	Sound text file (UTF-8)	New
pce.pat	.pce	Sound text file 2 (UTF-8)	New

3D Models

Pattern	File	Description	Status
b3d.pat	.b3d	B3D 1.1 tagged model format	Updated (TVertex44/64, surface, skinning)
gr2.pat	.gr2	Granny 2 format header	Stub (full parse needs Granny runtime)

Map / World

Pattern	File	Description	Status
tre.pat	.8 / .tre	8TRE octree map geometry	Updated (HEAD, LGTD, MATD, VTXD, TREE chunks)
Map.pat	.map	Aggregate of map chunks	Updated

GUI / Interface

Pattern	File	Description	Status
int.pat	.int	GUI screen layout (recursive objects, fragments, fonts)	Updated (label blocks, fragments, version branches)

Visual Effects

Pattern	File	Description	Status
rle.pat	.rle	RLE-encoded grayscale image	New
veg.pat	.veg	VFX/shader file	Updated (VFX blocks, property union)

Entity / Item Files

Pattern	File	Description	Status
CRT.pat	.crt	Creature/character	Updated (EEN2→GENT→GCRE→GCHR)
ITM.pat	.itm	Generic item	Updated (EEN2→GENT→GITM)
ARM.pat	.arm	Armor	Updated (EEN2→GENT→GITM→GIAR)
WEA.pat	.wea	Weapon	Updated (EEN2→GENT→GITM→GIWP)
AMO.pat	.amo	Ammo	Updated (EEN2→GENT→GITM→GIAM)
USE.pat	.use	Usable object	Updated (EEN2→GENT→GOBJ)
DOR.pat	.dor	Door	New (EEN2→GENT→GOBJ + GDOR trailer)
CON.pat	.con	Container	New (EEN2→GENT→GOBJ + GCON trailer)

Component Chunks (used by Map/Entity files)

Pattern	Description	Status
EEN2c.pat	Entity visual/inventory strings + EEOV	Fixed
EEOVc.pat	Inventory/overlay strings (s1..s5 + inv list)	Fixed (removed template, added bounds)
EMAPc.pat	Map metadata (3 strings, color, flags)	Updated
EME2c.pat	Map entity placement (name, Vector4, EEOV)	Fixed (added vector4 import)
EMEFc.pat	Map effect (string, Vector4, string, byte)	Updated
EMEPc.pat	Map entry point (index, position, rotation)	Updated
EMFGc.pat	Fog volume (heights, speeds, density)	Updated
EMNOc.pat	Map note/node (Vector2, texture, sr)	Updated
EMNPc.pat	Map navpoint chunks	Fixed (added count)
EMSDc.pat	Map sound (string, Vector3, string)	Fixed (import error)
EMTRc.pat	Trigger geometry (count + Vector3 array)	Fixed (added count)
EPTHc.pat	Path (name + Vector4 array)	Fixed (added count)
ExTRc.pat	Trigger action (type + string)	Updated
ECAMc.pat	Camera (Vector4)	Updated
_2MWTc.pat	Water/2MWT chunks	Fixed (added counts)
GENTc.pat	Generic entity stats (string refs, health, gap)	Updated (added Gap28to35)
GCREc.pat	Creature record (SPECIAL, skills, sockets, GWAM)	Updated (bounded arrays)
GCHRc.pat	Character name string	Updated
GITMc.pat	Item equip/sockets/flags	Updated
GIARc.pat	Armor resistances (6 values)	Updated
GIAMc.pat	Ammo stats (versioned: caliber, damage, etc.)	Updated (added version gating)
GIWPc.pat	Weapon data (versioned: class, calibers, attack modes)	Updated (added version gating)
GWAMc.pat	Weapon attack mode (versioned: anim, damage, range, AP)	Updated (added version gating)
GOBJc.pat	Object type (USE/DOR/CON)	Fixed (u8→u32)
socket.pat	Model/texture socket pair	Updated
skill.pat	Skill id/value pair	Fixed (u8+u8→u32+u32)
trigger.pat	EMTR + ExTR composite	Updated

Math Helpers

Pattern	Description
vector2.pat	2D float vector
vector3.pat	3D float vector
vector4.pat	4D float vector

Chunk Framing

Most Van Buren data files use a common chunk system:

char[4] tag       // "EMAP", "EME2", "GCRE", etc.
u32     version   // format version
u32     size      // total bytes including this 12-byte header
u8[]    payload   // size - 12 bytes

Import je.chunk for the ChunkHeader struct and helper functions.

Known Issues / TODO

1. GR2 pattern is header-only; full parsing requires the Granny runtime
2. RLZ (type 900) and RTD (type 1000) — format unknown, deferred for future reverse-engineering
3. Most chunk component patterns model payload-only; they must be used inside a chunk wrapper (tag + version + size) for correct offsets
4. Signedness: many patterns use u32 where the original source uses signed int; binary layout is identical but displayed values differ for negative numbers

File Extensions Used by Van Buren

From resource.rht type mapping:

Ext	Type	Description
.b3d	100	3D model (or .g3d if not "B3D " magic)
.tga	200	Texture (or .bmp if magic "BM")
.8	400	Octree map geometry (magic "8TRE")
.rlz	900	Unknown — no parser or text handling found
.rtd	1000	Unknown — no parser or text handling found
.map	1300	Map file
.crt	1400	Creature/character
.veg	1500	Visual effect
.int	1600	GUI screen
.rle	1700	RLE image
.itm	1800	Item
.psf	1900	Sound configuration text file (UTF-8)
.gsf	2000	Text file (UTF-8)
.gls	2100	Group list text file (UTF-8)
.sco	2200	Sound text file (UTF-8)
.pce	2300	Sound text file 2 (UTF-8)
.wea	2400	Weapon
.arm	2500	Armor
.dor	2600	Door
.use	2700	Usable object
.amo	3500	Ammo
.con	3600	Container
.txt	3700	Text file

References

• ImHex — The hex editor these patterns are built for