Skyrim Mod:Mod File Format/PERK

The PERK record is a complex structure of subrecords which must be in the correct order and format to be properly parsed by the game.

Main Record

C	Field	Name	Type/Size	Info
+	EDID		zstring	EditorID
-	VMAD		struct	Script data
-	FULL		lstring	Perk Name
+	DESC		dlstring	Description
-	ICON		zstring	Inventory image filename
*	CTDA		struct	Zero or more condition data subrecords for the perk to be available to the player
+	DATA		struct	uint8[5]: IsTrait Level NumRanks IsPlayable IsHidden
-	NNAM		formid	If present points to the next PERK
*			Perk Sections[]	See below.

Perk Sections

What follows are 1 or more perk sections. Each section starts with a PRKE subrecord and ends with a PRKF. The type of the section is indicated by the data bytes of the PRKE field. The subrecord types shared between the different types of perk sections have the following formats. (To reiterate, this is not the layout of any type of perk section; this is just a description of the details of the different forms the subrecords can take, depending on the perk section type.)

C	Field	Name	Type/Size	Info
+	PRKE		uint8[3]	uint8 - Type (See below for more details on the format of each section type) 00: perk section is Quest section 01: perk section is Ability section 02: perk section is Complex Entry Point section uint8: Rank - Value of 0 = Rank 1 uint8: Priority - Assumed to be how to order/iterate through perk sections
-	PRKC		uint8	Type - How to apply the conditions that follow. Has values of 0-2 but the actual values depend on the effect type. See the entry point EffectTypes for details. Perk Owner Target Attacker Attacker Weapon Spell Weapon Item Enchantment Locked Reference
*	CTDA		struct	Condition data for the section
-	EPFT		uint8	Type - The type of the perk data that follows in EPFD, EPF2, and EPF3 subrecords 01: EPFD is a float 02: EPFD is an 8 byte struct (float AV, float Factor)? 03: EPFD is a formid (?) 04: EPF2 = LString "verb" (feed) (optional) EPF3 = dword? (0=No EPFD? or 3=SPEL EPFD?) EPFD = formid (optional) 05: EPFD is a formid (SPEL) 06: EPFD is a zstring (GMST editorid?) 07: EPFD is a lstring (verb for custom activate actions)
-	EPF2 EPF3 EPFD			See EPFT
+	PRKF	Marker	null	Always the last subrecord in a perk section

Quest Section (0)

For type 00 sections the data is just setting the stage of a specific quest applied without conditions:

C	Field	Name	Type/Size	Info
+	PRKE		uint8[3]	Always: 0x00, 0x00, 0x00
+	DATA	Quest ID	uint8[8]	formid: Quest ID uint8: Stage uint8[3]: Null - Has junk data, presumably unused
+	PRKF	Marker	null

Ability Section (1)

For type 01 sections the data is simply a spell applied without conditions:

C	Field	Name	Type/Size	Info
+	PRKE		uint8[3]	Always: 0x01, 0x00, 0x00
+	DATA	Quest ID	formid	Spell ID? - Unsure if it is always a spell
+	PRKF	Marker	null

Complex Entry Point Section (2)

For type 02 sections there are one or more conditions which must be met in order to apply a variety of effects:

C	Field	Name	Type/Size	Info
+	PRKE		uint8[3]	Always: 0x02, 0x00, 0x00
+	DATA		uint8[3]	EffectType - What effect to apply for the section (see below) FunctionType - How to apply the effect? Affects what should be found in the EPFT/EPFD which follow (see below for more details) CondTypeCount - Number of different type of conditions to test for (01, 02 or 03). This value is presumably fixed according to the effect type and probably shouldn't be edited.
*			Condition Subsections[]	(See below.)
+	EPFT		uint8	DataType - Affects type of data that follows
?	EPFD		variable	See the above details on EPFT for which subrecords should be found here and their format
?	EPF2		uint32
?	EPF3		uint32
+	PRKF	Marker	null

Condition Subsection

C	Field	Name	Type/Size	Info
+	PRKC		uint8	Condition type
*	CTDA		struct	Condition data for the subsection

Perk Effect Types

The first byte in a DATA subrecord in a complex entry point section is the type of effect to apply and has the values as listed below. The effect type determines what sort of data follows and in what format.

Effect ID	Effect Type	Functions	Additional Data	Condition Types	Condition Type Count
0E	Activate	Add Activate Choice	Button Label Run Immediately Replace Default Apply Spell Script Fragment?	Perk Owner (0) and Target (1)	2
09	Add Level List On Death	Add Level List	LevelListID	Perk Owner and Target	2
05	Adjust Book Skill Points 1	All Value		Perk Owner	1
04	Adjust Limb Damage	All Value		Perk Owner, Attacker, Attacker Weapon	3
34	Apply Bashing Spell	Select Spell	SpellID	Perk Owner, Target	2
33	Apply Combat Hit Spell	Select Spell	SpellID	Perk Owner, Weapon, Target	3
35	Apply Reanimate Spell	Select Spell	SpellID	Perk Owner, Spell, Target	3
45	Apply Sneaking Spell	Select Spell	SpellID	Perk Owner	1
43	Apply Weapon Swing Spell	Select Spell	SpellID	Perk Owner, Attacker, Attacker Weapon	3
03	Calculate Mine Explode Chance	Value Types		Perk Owner, Item	2
01	Calculate My Critical Hit Chance	Value Types		Perk Owner, Weapon, Target	3
02	Calculate My Critical Hit Damage	Value Types		Perk Owner, Weapon, Target	3
00	Calculate Weapon Damage	Value Types		Perk Owner, Weapon, Target	3
4B	Can Dual Cast Spell	Value Types		Perk Owner, Spell	2
3D	Can Pickpocket Equipped Item	Value Types		Perk Owner, Target, Item	3
4A	Filter Activation	Value Types		Perk Owner, Target	2
0A	Get Max Carry Weight	Value Types		Perk Owner	1
07	Get Should Attack	Value Types		Perk Owner, Attacker	2
10	Ignore Broken Lock	Value Types		Perk Owner	1
0F	Ignore Running During Detection	Value Types		Perk Owner	1
41	Make Lockpicks Unbreakable	Value Types		Perk Owner	1
50	Mod Number of Enchantments Allowed	Value Types		Perk Owner	1
20	Mod Armor Weight	Value Types		Perk Owner, Item	2
23	Mod Attack Damage	Value Types		Perk Owner, Weapon, Target	3
1A	Mod Bashing Damage	Value Types		Perk Owner, Target	2
2E	Mod Bribe Amount	Value Types		Perk Owner, Target	2
2F	Mod Detection Light	Value Types		Perk Owner, Target	2
30	Mod Detection Movement	Value Types		Perk Owner, Target	2
2D	Mod Favor Points	Value Types		Perk Owner, Target	2
24	Mod Incoming Damage	Value Types		Perk Owner, Attacker, Attacker Weapon	3
2A	Mod Incoming Spell Duration	Value Types		Perk Owner, Spell	2
29	Mod Incoming Spell Magnitude	Value Types		Perk Owner, Spell	2
21	Mod Incoming Stagger	Value Types		Perk Owner, Attacker	2
27	Mod Percent Blocked	Value Types		Perk Owner	1
2B	Mod Player Intimidation	Value Types		Perk Owner, Target	2
2C	Mod Player Reputation	Value Types		Perk Owner	1
53	Mod Poison Dose Count	Value Types		Perk Owner, Weapon, Spell	3
1C	Mod Power Attack Damage	Value Types		Perk Owner, Weapon, Target	3
1B	Mod Power Attack Stamina	Value Types		Perk Owner, Weapon	2
1F	Mod Secondary Value Weight	Value Types		Perk Owner, Spell, Target	3
28	Mod Shield Deflect Arrow Chance	Value Types		Perk Owner	1
52	Mod Shout OK	Value Types		Perk Owner	1
4F	Mod Soul Gem Enchanting	Value Types		Perk Owner, Enchantment, Item	3
31	Mod Soul Gem Recharge	Value Types		Perk Owner, Item	2
37	Mod Spell Casting Sound Event	Value Types		Perk Owner, Spell	2
26	Mod Spell Cost	Value Types		Perk Owner, Spell	2
1E	Mod Spell Duration	Value Types		Perk Owner, Spell, Target	3
1D	Mod Spell Magnitude	Value Types		Perk Owner, Spell, Target	3
25	Mod Target Damage Resistance	Value Types		Perk Owner, Weapon, Target	3
22	Mod Target Stagger	Value Types		Perk Owner, Target	2
0B	Mod Addiction Chance	Value Types		Perk Owner	1
42	Mod Alchemy Effectiveness	Value Types		Perk Owner	1
55	Mod Armor Rating	Value Types		Perk Owner, Item	2
14	Mod Bow Zoom	Value Types		Perk Owner, Weapon	2
08	Mod Buy Prices	Value Types		Perk Owner, Target	2
44	Mod Commanded Actor Limit	Value Types		Perk Owner, Spell	2
39	Mod Detection Sneak Skill	Value Types		Perk Owner, Target	2
4D	Mod Enchantment Power	Value Types		Perk Owner, Enchantment, Item	3
11	Mod Enemy Critical Hit Chance	Value Types		Perk Owner, Weapon, Target	3
3A	Mod Falling Damage	Value Types		Perk Owner	1
57	Mod Ingredients Harvested	Value Types		Perk Owner, Item	2
48	Mod Ingredient Effects Learned	Value Types		Perk Owner, Spell	2
3E	Mod Lockpick Level Allowed	Value Types		Perk Owner	1
3B	Mod Lockpick Sweet Spot	Value Types		Perk Owner, Locked Reference	2
56	Mod Lockpick Crime Chance	Value Types		Perk Owner, Locked Reference	2
5A	Mod Lockpick Key Reward Chance (Wax Key)	Value Types		Perk Owner, Locked Reference	2
13	Mod Max Placeable Mines	Value Types		Perk Owner	1
38	Mod Pickpocket Chance	Value Types		Perk Owner, Target, Item	3
46	Mod Player Magic Slowdown	Value Types		Perk Owner, Spell	2
0D	Mod Positive Chem Duration	Value Types		Perk Owner	1
59	Mod Potions Created (Create Duplicate Potion)	Value Types		Perk Owner, Spell	2
15	Mod Recover Arrow Chance	Value Types		Perk Owner	1
06	Mod Recovered Health	Value Types		Perk Owner	1
3C	Mod Sell Prices	Value Types		Perk Owner, Target	2
16	Mod Skill Use	Value Types		Perk Owner	1
12	Mod Sneak Attack Multiplier	Value Types		Perk Owner, Weapon, Target	3
4E	Mod Soul Percent Captured to Weapon	Value Types		Perk Owner, Target, Item	3
58	Mod Spell Range to Location	Value Types		Perk Owner, Spell	2
19	Mod Telekinesis Damage	Value Types		Perk Owner, Target	2
18	Mod Telekinesis Damage Multiplier	Value Types		Perk Owner	1
17	Mod Telekinesis Distance	Value Types		Perk Owner	1
4C	Mod Tempering Health	Value Types		Perk Owner, Item	2
47	Mod Ward Magic Absorption Percent	Value Types		Perk Owner, Spell	2
49	Purify Alchemy Ingredients	Value Types		Perk Owner	1
51	Set Activate Label	SetText	Text	Perk Owner, Target	2
36	Set Boolean Graph Variable	SelectText	Text	Perk Owner	1
3F	Set Lockpick Start Position	Value Types		Perk Owner	1
40	Set Progression Picking	Value Types		Perk Owner	1
32	Set Sweep Attack	Value Types		Perk Owner, Weapon	2
54	Should Apply Placed Item	Value Types		Perk Owner, Target, Item	3

Function Types

Capitalized variables are input in section data. Each type uses the following format, with the meanings of each field outlined in the table below that.

Function ID	Function	New Value	EPFT	EPF2	EPF3	EPFD
01	Set Value	VALUE	0x01			float VALUE
02	Add Value	Value + AMOUNT	0x01			float AMOUNT
03	Multiply Value	Value * FACTOR	0x01			float AMOUNT
04	Add Range to Value	Value + random(MIN, MAX)	0x02			float MIN, float MAX
05	Add Actor Value Mult	Value + AV * FACTOR	0x02			float AV, float FACTOR
06	Absolute	Abs(Value)
07	Negative ABS Value	-Abs(Value)
08	Add Level List (Only EffectType 0x09)		0x03			formid LevelListID
09	Add Activate Choice (Only EffectType 0x0E)		0x04	lstring (button label if present)	uint16 - Flags1: 0x01 = Run Immediately (No button label) 0x02 = Replace Default uint16 - Flags2: 0x03 = Spell? 0x04 = Script Fragment? (Script fragment info added to record VMAD)	formid SpellID (if present)
0A	Select Spell (Only EffectTypes 0x33, 0x34, 0x35, 0x43, 0x45)		0x05			formid SpellID
0B	Select Text (Only EffectType 0x36)		0x06	zstring (usually a GMST editor ID?)
0C	Set AV Mult	AV * FACTOR	0x02			float AV, float FACTOR
0D	Multiply AV Mult	Value * AV * FACTOR	0x02			float AV, float FACTOR
0E	Multiply 1 + AV Mult	Value * (1 + AV * FACTOR)	0x02			float AV, float FACTOR
0F	Set Text (Only EffectType 0x51)		0x07			lstring