Tes5Mod:Mod File Format/RACE

RACE records contain information on character and creature races.

There are a lot of fields here, many in repeating sets, and a lot of markers.  Generally all sets of data are preceded by a gender-specifying marker, MNAM for male, FNAM for female.  There are also markers indicating the presence of certain sets (or not).

General record structure (in order of appearance):
General Data 
Male then female skeletal model separated by MNAM/FNAM
General Data
Repeating pairs of ATKD/ATKE (attack data)
Male then female egt model separated by MNAM/FNAM, preceded by NAM1
Male then female havok model separated by MNAM/FNAM, preceded by NAM3
General Data
32x Body Part Strings - User defined Biped Object Names stord in each NAME Subrecord
EQUP info
Repeating pairs of PHTN/PHWT (facial expression data)
Male then female head data separated by MNAM/FNAM (and NAM0) in the following order:
Default headparts
MPAI/MPAV - Morph and Morph Values
Racial presets
Hair colors
Featuresets 
Repeating tint fieldsets (TINI/TINC/TINV/TIRS) optionally with 2nd set (TINT/TINP/TIND)


{| class="wikitable" border="1" width="100%" 
! width="3%" | C
! width="10%" | SubRecord
! width="15%" | Name
! width="12%" | Type/Size
! | Info
|- 
| + || EDID || editorId || zstring || Editor id
|-
| - || FULL || full name || lstring || Full (in-game) name 
|-
| + || DESC || description || lstring || Description shown in-game when selecting the player's race (or 0)
|-
| - || SPCT || spellCount || uint32 || number of SPLO records that follow. If the race has no bonus spells, SPCT and SPLO are not present.
|-
| * || SPLO || spell || formID || Racial SPEL or SHOU
|-
| - || WNAM || skin || formid || ARMO record
|-
| + || BODT || body template || struct || 12-byte struct (same as ARMO)
: uint32 Biped Object Flags
: uint32 General Flags (Undetermined)
: uint32 Armor Type - Clothing is default if not given
|-
| - || KSIZ || KSIZ || uint32 || keyword count
|-
| - || KWDA || KWDA || formID || KYWD array of KSIZ
|-
| + || DATA || General race stats || struct || 128-byte struct (v40) or 164-byte struct (v43)
:uint8 - Skill 1 (Actor list value)
:uint8 - Racial bonus for skill 1
:uint8 - Skill 2 (Actor list value)
:uint8 - Racial bonus for skill 2
:uint8 - Skill 3 (Actor list value)
:uint8 - Racial bonus for skill 3
:uint8 - Skill 4 (Actor list value)
:uint8 - Racial bonus for skill 4
:uint8 - Skill 5 (Actor list value)
:uint8 - Racial bonus for skill 5
:uint8 - Skill 6 (Actor list value)
:uint8 - Racial bonus for skill 6
:uint8 - Skill 7 (Actor list value)
:uint8 - Racial bonus for skill 7
:uint16 - "Unused (padding)"
:float - Height (male)
:float - Height (female)
:float - Weight (male)
:float - Weight (female)
:uint32 - Flags.
::0x00000001 - Playable
::0x00000002 - FaceGen Head
::0x00000004 - Child
::0x00000008 - Tilt Front/Back
::0x00000010 - Tilt Left/Right
::0x00000020 - No Shadow
::0x00000040 - Swims
::0x00000080 - Flies
::0x00000100 - Walks
::0x00000200 - Immobile
::0x00000400 - Not Pushable
::0x00000800 - No Combat In Water
::0x00001000 - No Rotating to Head-Track
::0x00002000 - Don't Show Blood Spray
::0x00004000 - Don't Show Blood Decal
::0x00008000 - Uses Head Track Anims
::0x00010000 - Spells Align w/Magic Node
::0x00020000 - Use World Raycasts For FootIK
::0x00040000 - Allow Ragdoll Collision
::0x00080000 - Regen HP In Combat
::0x00100000 - Can't Open Doors
::0x00200000 - Allow PC Dialogue
::0x00400000 - No Knockdowns
::0x00800000 - Allow Pickpocket
::0x01000000 - Always Use Proxy Controller
::0x02000000 - Don't Show Weapon Blood
::0x04000000 - Overlay Head Part List {> Only one can be active   Only one can be active   mesh-morphing files for body weight adjustments. Every race added to the game either needs a set of these or needs a NAM8 indicating which other race's morph files to use. If the race is just a copy of a vanilla one, setting NAM8 to that vanilla race is a safe "fire and forget" solution. If it's something outlandish like a playable Goblin race, custom   files will actually need to be generated with mesh tools and added to the FormID Lists mentioned in the CK errors, so that something like weight 35 or weight 50 can be generated properly from the   and   meshes. If the race is unplayable and only for one or a few NPCs at fixed 0 or 100 weights, such that middling weights are never needed, then setting NAM8 to any vanilla race will have no effect on the game but will stop pop-up errors in the CK.

The RNAM record being set to a vanilla race obviates any need to change armor, weapon, and other records to account for the new race.  This is perhaps the most common oversight in race modding.  It is not actually practical to do anything else but set the RNAM to a vanilla race with the same general body/head shape and gear-using capabilities, because there are thousands of armor and clothing mods and you won't be able to add your custom race to all of them, item by item. Even doing it for vanilla gear only would be incredibly tedious and ultimately pointless.  This sort of thing is one reason that custom playable new races for Skyrim are markedly less common for than for Oblivion and Morrowind, which had fewer complications of this sort.  It's simply not immediately obvious to a new modder what to do to make a new race work properly, especially once third-party gear mods are involved.  Fortunately, the RNAM is another situation where "close enough" should work. Most of the vanilla humanoid races are equivalent when it comes to equippability of most gear types. Some exceptions are that various Elven races have specific heads meshes and equip variant headgear meshes (if your new race has a head based on Altmer, don't pick Nord as the RNAM); beast races do as well, and cannot even equip all headgear types at all due to their snouts; and vampire race variants (since  ) will no longer equip crossbows, the weapon specialized for hunting them.

The gist of the above applies to creatures as well.  If you design a rideable giant Nix Hound as a mount, it will need: 1) either an ATKR of a comparably semi-fearsome quadruped, or comprehensive custom combat-related records and stats; 2) either custom   files and FormID List entries for them, or fixed 0 and 100 weights only, with a dummy NAM8, perhaps for Horse or Sabre Cat; and 3) an RNAM set to the Horse race specifically if you want it to be compatible with saddles and with barding (horse armor) mods, and do not want it capable of equipping humanoid gear (your Thoroughbred Nix probably shouldn't be trying to using a sword).  You may need to do mesh and skeleton adjustment work to make sure your hound-mount's body will actually fit such gear properly (which may not be as hard as it sounds; the basic skeletal armature of the in-game horse is the same as that of a dog and wolf).