Oblivion Mod:FormID Fixup

Many mod utilities for Oblivion will need to be able to properly handle formids especially when merging plugins where modindexes will have to change. In order to do this one must know all places in the ESP format where formids are stored. This page attempts to describe the process of fixing formids when loading or merging plugins as well as the locations in the ESP format where formids are known to stored.

FormID Locations

Most of the following formid locations have been verified with a high, but not complete, amount of confidence except where noted.

Record	Subrecord	Size	Byte	Allowed Types	Notes
[All]	[Header]	20	12	Any	All records have a formid in their header
GRUP	[Header]	20	12	Various	Occurs only in Worldspace, Cell, Persistent, Temporary, Distant and Topic group types
ACHR	XESP	8	0	REFR, ACRE, ACHR
	XPCI	4	0	CELL
	XMRC	4	0	REFR
	NAME	4	0	NPC_
	XHRS	4	0	ACRE
ACRE	XOWN	4	0	FACT, NPC_
	XESP	8	0	REFR, ACRE, ACHR
	NAME	4	0	CREA
ACTI	SCRI	4	0	SCPT
	SNAM	4	0	SOUN
ALCH	SCIT	16	0	SCPT
	SCRI	4	0	SCPT
AMMO	ENAM	4	0	ENCH
ANIO	DATA	4	0	IDLE
APPA	SCRI	4	0	SCPT
ARMO	SCRI	4	0	SCPT
	ENAM	4	0	ENCH
BOOK	SCRI	4	0	SCPT
	ENAM	4	0	ENCH
BSGN	SPLO	4	0	SPEL
CELL	XOWN	4	0	FACT, NPC_
	XCCM	4	0	CLMT
	XGLB	4	0	GLOB
	XCWT	4	0	WATR
	XCLR	4-28	0/4/8/...	REGN	Array of regions
CLAS	None
CLMT	WLST	8, 24, 56	0/8/16/...	WTHR	An array of 8 byte structures with a formid in the first 4 bytes
CLOT	SCRI	4	0	SCPT
	ENAM	4	0	ENCH
CONT	CNTO	8	0	Various items
	SCRI	4	0	SCPT
	QNAM	4	0	SOUN
	SNAM	4	0	SOUN
CREA	SPLO	4	0	SPEL, LVSP
	CNT0	8	0	Various items
	PKID	4	0	PACK
	CSCR	4	0	CREA
	CSDI	4	0	SOUN
	SCRI	4	0	SCPT
	INAM	4	0	LVLI
	ZNAM	4	0	CSTY
	SNAM	8	0	FACT
CSTY	None
DIAL	QSTI	4	0	QUST
DOOR	SCRI	4	0	SCPT
	BNAM	4	0	SOUN
	ANAM	4	0	SOUN
	TNAM	4	0	CELL, WRLD
	SNAM	4	0	SOUN
EFSH	None
ENCH	SCIT	16	0	SCPT
EYES	None
FACT	XNAM	8	0	FACT
FLOR	PFIG	4	0	INGR
	SCRI	4	0	SCPT
FURN	SCRI	4	0	SCPT
GLOB	None
GMST	None
GRAS	None
HAIR	None
IDLE	DATA	8	0	IDLE, NULL
	DATA	8	4	IDLE, NULL
	CTDA	24	12	Various	Only if function (byte 8) is a certain type (see below).
	CTDA	24	16	Various	Only if function (byte 8) is a certain type (see below).
INFO	CTDT	20	12	Various	Only if function (byte 8) is a certain type (see below).
	CTDT	20	16	Various	Only if function (byte 8) is a certain type (see below).
	CTDA	24	12	Various	Only if function (byte 8) is a certain type (see below).
	CTDA	24	16	Various	Only if function (byte 8) is a certain type (see below).
	SCRO	4	0	Various
	QSTI	4	0	QUST
	TCLT	4	0	DIAL
	TCLF	4	0	DIAL
	NAME	4	0	DIAL
INGR	SCIT	16	0	SCPT
	SCRI	4	0	SCPT
KEYM	SCRI	4	0	SCPT
LAND	ATXT	8	0	LTEX, NULL
	BTXT	8	0	LTEX
	VTEX	256	*	LTEX, NULL	Array of formids
LIGH	SCRI	4	0	SCPT
	SNAM	4	0	SOUN
LSCR	LNAM	12	0	CELL, WRLD, NULL
	LNAM	12	4	NULL, WRLD
LTEX	GNAM	4	0	GRAS
LVLC	LVLO	8, 12	4	NPC_, CREA, LVLC	Most LVLO subrecords are 12 bytes (only 1 in 2822 is 8 bytes)
	SCRI	4	0	SCPT
	TNAM	4	0	NPC_, CREA
LVLI	LVLO	8, 12	4	Various items
LVSP	LVLO	12	4	SPEL, LVSP
MGEF	DATA	64	24	LIGH, NULL
	DATA	64	32	EFSH, NULL
	DATA	64	36	EFSH, NULL
	DATA	64	40	SOUN
	DATA	64	44	SOUN
	DATA	64	48	NULL, SOUN
	DATA	64	52	SOUN
MISC	SCRI	4	0	SCPT
NPC_	SPLO	4	0	LVSP, SPEL
	CNTO	8	0	Various
	PKID	4	0	PACK
	SCRI	4	0	SCPT
	ENAM	4	0	EYES
	HNAM	4	0	HAIR
	CNAM	4	0	CLASS
	RNAM	4	0	RACE
	INAM	4	0	LVLI
	ZNAM	4	0	CSTY
	SNAM	8	0	FACT
PACK	CTDA	24	12	Various:	Only if function (byte 8) is a certain type (see below).
	CTDA	24	16	Various: NULL, NPC_, ACHR	Only if function (byte 8) is a certain type (see below).
	CTDT	20	12	Various	Only if function (byte 8) is a certain type (see below).
	CTDT	20	16	Various	Only if function (byte 8) is a certain type (see below).
	PLDT	12	4	Various	Only if type (byte 0) is 0-4.
	PTDT	12	4	Various	Only if type (byte 0) is 0-1.
PGRD	PGRL	8-172	0	REFR	Appears to be a REFR formid followed by a variable array of longs (unknown).
QUST	CTDA	24	12	Various	Only if function (byte 8) is a certain type (see below).
	CTDA	24	16	Various	Only if function (byte 8) is a certain type (see below).
	SCRI	4	0	SCPT
	QSTA	8	0	REFR, ACRE, ACHR
	SCRO	4	0	Various
RACE	SPLO	4	0	SPEL
	DNAM	8	0	HAIR
	DNAM	8	4	HAIR
	ENAM	4 or 12	0	EYES
	ENAM	12	4	EYES
	ENAM	12	8	EYES
	VNAM	8	0	RACE, NULL
	VNAM	8	4	RACE
	XNAM	8	0	RACE
REFR	XRTM	4	0	REFR
	XTEL	28	0	REFR
	XLOC	12, 16	4	KEYM, NULL
	XOWN	4	0	FACT, NPC_
	XESP	8	0	REFR, ACRE, ACHR
	XGLB	4	0	GLOB
	XPCI	4	0	CELL
	XTRG	4	0	REFR, ACHR
	NAME	4	0	Various objects
REGN	RDWT	8-48	0/8/16...	WTHR	Array of 8 byte structures with a weather formid in the first 4 bytes
	RDGS	32	0/8/16/...	GRAS	Array of 8 byte structures with a grass formid in the first 4 bytes
	RDOT	416-6916	0/52/104/...	LTEX, STAT?	Appears to be an array of structures 52 bytes in size with a formid at byte 0 (not confirmed)
	RDSD	12-384	0/12/24...	SOUN	Seems to be an array of 12 byte structures with a sound formid in the first 4 bytes
	WNAM	4	0	WRLD
ROAD	None
SBSP	None
SCPT	SCRO	4	0	Various
SGST	SCIT	16	0	SCPT
SKIL	None
SLGM	SCRI	4	0	SCPT
SOUN	None
SPEL	SCIT	16	0	SCPT
STAT	None
TES4	None
TREE	None
WATR	SNAM	4	0	SOUN
WEAP	SCRI	4	0	SCPT
	ENAM	4	0	ENCH
WRLD	NAM2	4	0	WATR
	CNAM	4	0	CLMT
	WNAM	4	0	WRLD
WTHR	SNAM	8	0	SOUN

Locations Not a Formid

The following locations appear at first to be a possible formid location but in closer detail are not.

Record	Subrecord	Size	Byte	Apparent Types	Notes
IDLE, INFO, QUST, PACK	CTDA	24	20	Various	Seems to never be a formid (is almost always 0).
REGN	RDAT	8	0	NPC_, DOOR, STAT	This appears to be a formid but it may just be coincidence (the purpose of RDAT is not known)
	RDAT	8	4	CELL, REFR, LAND	This appears to be a formid but it may just be coincidence (the purpose of RDAT is not known)

CTDA/CTDT Functions

The CTDA and CTDT subrecords that occur in IDLE, INFO, QUST, and PACK records contain formids only in some cases. The basic structure of these records is:

  byte     CompareTypeAndFlags
  byte[3]  Unknown
  float    CompareValue
  long     FunctionIndex
  long     Parameter1
  long     Parameter2
  long     Unknown    (only in CTDA)

Parameters 1 and 2 can represent a variety of values depending on what the function used accepts, including formids. The following table lists the functions that accept one or two formids as input (see also Function Indices):

Function	Index	Parameter1	Parameter2
GetCrime	122	Actor Reference	Crime Type
GetDeadCount	84	Actor
GetDetected	45	Actor Reference
GetDetectionLevel	180	Actor Reference
GetDisposition	76	Actor Reference
GetDistance	1	Reference
GetEquipped	182	Object
GetFactionRank	73	Faction
GetFactionRankDifference	60	Faction	Actor Reference
GetFriendHit	288	Actor Reference
GetGlobalValue	74	Global
GetHeadingAngle	99	Reference
GetInCell	67	Cell
GetInCellParam	230	Cell	Reference
GetInFaction	71	Faction
GetInSameCell	32	Reference
GetInWorldspace	310	Worldspace
GetIsClass	68	Class
GetIsClassDefault	228	Class
GetIsCurrentPackage	161	AI Package
GetIsCurrentWeather	149	Weather
GetIsID	72	Object
GetIsPlayerBirthSign	224	Birthsign
GetIsRace	69	Race
GetIsReference	136	Reference
GetIsUsedItem	246	Object
GetItemCount	47	Object
GetLineOfSight	27	Reference
GetPCExpelled	193	Faction
GetPCFactionAttack	199	Faction
GetPCFactionMurder	195	Faction
GetPCFactionSteal	197	Faction
GetPCFactionSubmitAuthorithy	201	Faction
GetPCInFaction	132	Faction
GetPCIsClass	129	Class
GetPCIsRace	130	Race
GetQuestRunning	56	Quest
GetQuestVariable	79	Quest	Variable
GetScriptVariable	53	Reference	Variable
GetShouldAttack	66	Actor Reference
GetStage	58	Quest
GetStageDone	59	Quest	Stage
GetTalkedToPCParam	172	Actor Reference
HasMagicEffect	214	Magic Effect
IsCellOwner	280	Cell	Owner (Optional)
IsCurrentFurnitureObj	163	Furniture
IsCurrentFurnitureRef	162	Reference
IsOwner	278	Owner (Optional)
IsSpellTarget	223	Magic Enchantment, Spell, or Ingredient
SameFaction	42	Actor Reference
SameRace	43	Actor Reference
SameSex	44	Actor Reference

Notes

• GMSTs do not appear to have their formids used anywhere.
• Some subrecord data only represents formids in some cases, depending on another value in the subrecord (ex: CTDA). This makes it difficult to confirm formid locations without completely knowing the file format.
• The formid 0x0000014 seems to represent the player reference object (i.e., the instance of the player in the game and not the actual player NPC). This formid does not actually exist in Oblivion.esm and is presumably hardcoded.
• The Oblivion.esm file contains many invalid formids in some subrecords. For example in SCIT subrecords there occurs several formid values greater than 0x01000000 which are not valid as well as one SCIT subrecord that actually specifies a LAND record (it must specify a SCPT record). Once again this makes it difficult or impossible to confirm formid locations when the data itself is not valid.
• Some subrecords which probably should be a fixed size actually have a variable size (ex: LVLO subrecords in LVLC records). This maybe due to versioning issues (the subrecord size was changed at some point but only updated or new subrecords had their size changed). When reading and modifying subrecord data for formid fixups or other purposes ensure you use the record size as read from the file. There are also some almost identical subrecords that appear to be from versioning (ex: the 16 byte CTDT appears to be identical to the 20 byte CTDA).

References

• ScripterRon's TES4Plugin utility source
• Ghostwheel's Tes4.xml (Must access main Ghostwheel site first)
• The ObTestFile module run with stats enabled on Oblivion.esm (use options "/o /m /s"). Currently not yet released (contact the Author for more information).