By Mirex, JWP, random_npc and myst6re (and now HobbitDur too). Edit: We now know the animation and skeleton- see https://github.com/MaKiPL/OpenVIII/blob/4ac151daad7cd1475eb0694dd0715bc35d7a4b39/FF8/debug_battleDat.cs

DAT file is divided into 11 sections (except for c0m127.dat, which contains only 2 sections : 7th and 8th).

Offset Length Description
0 4 bytes Number of sections (always =11, except for c0m127.dat)
4 nbSections * 4 bytes Section Positions
4 + nbSections * 4 4 bytes File size

Section 1: Skeleton

Offset Length Description
0 2 bytes Number of bones
2 6 bytes Unknown
8 s16f (divide by 4096f) scaleX
10 s16f (divide by 4096f) scale -Z
12 s16f (divide by 4096f) scale Y
14 2 bytes Unknown
16 Number of bones * 48 bytes Bones

Bone struct

Offset Length Description
0 2 bytes Parent id
2 s16f (divide by 4096f) Bone size (?)
4 s16f (divide by 4096f) unknown, multiplied by 360f
6 s16f (divide by 4096f) unknown, multiplied by 360f
8 s16f (divide by 4096f) unknown, multiplied by 360f
10 s16f (divide by 4096f) unknown
12 s16f (divide by 4096f) unknown
14 s16f (divide by 4096f) unknown
16 28 bytes Unknown (often empty)

Section 2: Model geometry

Header (data sub table)

Offset Length Description
0 4 bytes Number of objects
4 nbObjects * 4 bytes Object Positions
4 + nbObjects * 4 Varies Object Data (see below)
Varies 4 bytes Total count of vertices

Object Data

Offset Length Description
0 2 bytes Number of Vertices Data
2 Varies * NbVerticesData Vertices Data (see below)
Varies 4 - (absolutePosition % 4) Padding (0x00)
Varies 2 bytes Num triangles
Varies 2 bytes Num quads
Varies 8 bytes Always empty
Varies numTriangles * 16 bytes Triangles
Varies numQuads * 20 bytes Quads

Vertice Data

Offset Length Description
0 2 bytes Bone id
2 2 bytes Number of vertices
4 nbVertices * 6 bytes Vertices (nbVertices * 3 shorts)

Useful structures

struct vertice {
     sint16    x, y, z;
};

(sizeof = 6)

struct triangle {
     uint16    vertex_indexes[3]; // vertex_indexes[0] &= 0xFFF, other bits are unknown
     uint8 texCoords1[2];
     uint8 texCoords2[2];
     uint16    textureID_related;
     uint8 texCoords3[2];
     uint16    u; // textureID_related2
};

(sizeof = 16)

struct quad {
     uint16    vertex_indexes[4]; // vertex_indexes[0] &= 0xFFF, other bits are unknown
     uint8 texCoords1[2];
     uint16    textureID_related;
     uint8 texCoords2[2];
     uint16    u; // textureID_related2
     uint8 texCoords3[2];
     uint8 texCoords4[2];
};

(sizeof = 20)

Section 3: Model animation

Header (data sub table)

Offset Length Description
0 4 bytes Number of animations
4 nbAnimations * 4 bytes Animations Pointers
AnimPointer Varies Animation

Animation

Offset Length Description
0 1 byte Number of frames
1 Varies Animation frame

Animation frame

Each frame is one vector location and BonesCount*RotationVectorData. Vector location is used to manipulate the model in world space, where all the animation is rotating each bone. The frames work accumulatively, so in order to get the final rotation at in example frame 5, you have to add all rotations from frames 0,1,2,3 and 4.

Offset Length Description
0 LocationVectorData LocationVectorData
Varies 1 BIT Mode bit (contains additional info check)
Varies RotationVectorData * bonesCount Rotation Vector data per bone

Location vector data

Offset Length Description
0 PositionType Location X
Varies PositionType Location Y
Varies PositionType Location Z

Rotation vector data

Offset Length Description
0 RotationType Rotation X
Varies RotationType Rotation Y
Varies RotationType Rotation Z
Varies 1 BIT bUnk1
Varies 0 if bUnk1==0, else 16 BITs Unk1 data
Varies 1 BIT bUnk2
Varies 0 if bUnk2==0, else 16 BITs Unk2 data
Varies 1 BIT bUnk3
Varies 0 if bUnk3==0, else 16 BITs Unk3 data

We don’t know what the Unk1, Unk2 and Unk3 do. Enemies works without them, but as it’s important to keep up with the current bit position, we need to read it anyway

Position type

Position is BIT length. First we read the count of bits to read by reading first 2 bits.

Offset Length Description
0 2 BITs PositionTypeBits
0+0b11 PositionTypeBits Vector axis

PositionTypeBits

PositionTypeBits value Bits to read for one vector axis
0b00 3
0b01 6
0b10 9
0b11 16

Rotation type

Rotation is also BIT length. First read first bit to see, if there’s rotation data. If no, continue. If yes, then read the rotation data similar to Position Type

Offset Length Description
0 1 BIT IsRotationTypeAvailable
0+0b1 2 BIT RotationTypeBits
0+0b100 RotationTypeBits Rotation vector axis (pitch/yaw/roll)

RotationTypeBits

PositionTypeBits value Bits to read for one vector axis
0b00 3
0b01 6
0b10 8
0b11 12

Section 4: Texture animation data

Optional section, often empty. It contains info on animated texture (like blink-eyes) It starts with a list of offset followed by data that look like this:

struct texAnim
{
	uint8 textureNum;
	uint8 originalUCoord; //All UV coords here are for the upper left corner
	uint8 originalVCoord;
	uint8 regionUSize;
	uint8 regionVSize;
	uint8 copiedRegionCount; //1 less than the actual number
	uint8 unknown1;
	uint8 unknown2;
	//Insert remaining UV coords here
};

Refer to this message for more info: Qhimm message

Section 5: Animation sequences

Contain sequence of animation. Not much known yet, all info are found here: Qhimm message

Header

Offset Length Description
0 2 bytes Number of sequences
2 nbSequences * 2 bytes Sequences Positions

Section 6: Camera sequence

Not analysed, but defined camera work.

Section 7: Informations & stats

Offset Length Description
0 24 bytes Monster name
24 4 bytes HP values
28 4 bytes Str values
32 4 bytes Vit values
36 4 bytes Mag values
40 4 bytes Spr values
44 4 bytes Spd values
48 4 bytes Eva values
52 16*4 bytes Abilities, low level
116 16*4 bytes Abilities, med level
180 16*4 bytes Abilities, high level
244 1 byte Med level start
245 1 byte High level start
246 1 byte Unknown (flags, 3 bits used)
247 1 byte [LSB] Zombie / Fly / zz1 / LvUP-Down Immunity / HP Hidden / Auto-Reflect / Auto-Shell / Auto-Protect [MSB]
248 3 bytes Cards (low/med/high)
251 3 bytes Devour (low/med/high)
254 1 byte [LSB] zz1 / zz2 / unused / unused / unused / unused / Diablos missed / Always obtains card [MSB]
255 1 byte Unknown (flags, 4 bits used)
256 2 bytes Extra EXP
258 2 bytes EXP
260 8 bytes Draw (low)
268 8 bytes Draw (med)
276 8 bytes Draw (high)
284 8 bytes Mug (low)
292 8 bytes Mug (med)
300 8 bytes Mug (high)
308 8 bytes Drop (low)
316 8 bytes Drop (med)
324 8 bytes Drop (high)
332 1 byte Mug rate
333 1 byte Drop rate
334 1 byte Padding (0x00)
335 1 byte APs
336 16 bytes Renzokuken data: 8 renzokuken depending on the level of crisis.
Each 2 byte is a special action (for example 332 is a renzokuen with 7hit)
352 8 bytes Elemental resistance (Fire, Ice, Thunder, Earth, Poison, Wind, Water, Holy)
360 20 bytes Mental resistance (Death, Poison, Petrify, Darkness, Silence, Beserk, Zombie, Sleep,
Haste, Slow, Stop, Regen, Reflect, Doom, Slow Petrify, Float, Confuse, Drain, Expulsion, ???)

Abilities

typedef struct {
    uint8 kernel_id;
    uint8 unknown;
    uint16 ability_id;
}

kernel_id is the used table in kernel.bin. May be 0x02 (= magic), 0x04 (= item) or 0x08 (= monster ability). ability_id is the ability in the selected kernel table.

Draw/mug/drop

typedef struct {
    uint8 id_1; // magic_id for draw, item_id for mug & drop
    uint8 qty_1; // quantities are always 0 for draw
    uint8 id_2;
    uint8 qty_2;
    uint8 id_3;
    uint8 qty_3;
    uint8 id_4;
    uint8 qty_4;
}

Section 8: Battle scripts/AI

Offset Length Description
0 4 bytes Number of sub-sections
4 4 bytes Offset to AI sub-section
8 4 bytes Offset to text offsets
12 4 bytes Offset to text sub-section

AI

Offset Length Description
0 4 bytes Offset to init code
4 4 bytes Offset to code executed at ennemy’s turn
8 4 bytes Offset to counterattack code
12 4 bytes Offset to death code
16 4 bytes Offset to “before dying or taking a hit”

Texts

Text offsets is a list of text positions (2 bytes each) in the text sub-section.

Section 9: Sounds

Contains AKAO sequences (can be empty).

Offset Length Description
0 2 bytes Number of AKAOs
2 nbAKAOs * 2 bytes AKAOs Positions
2 + nbAKAOs * 2 2 bytes End of section 9
4 + nbAKAOs * 2 Varies * nbAKAOs AKAOs

Section 10: Sounds/Unknown

Contains AKAO sequence + unknown data (can be empty).

Section 11: Textures

Contains some TIMs.

Offset Length Description
0 4 bytes Number of TIMs
4 nbTIMs * 4 bytes TIMs Positions
4 + nbTIMs * 4 4 bytes End of file
8 + nbTIMs * 4 Varies * nbTIMs TIMs