Sonic Adventure 2/Model Formats

SCHG: Sonic Adventure 2
Dreamcast GameCube PC
Sonic Adventure 2 (Dreamcast) Main Article Object Editing Editing Objects File Name Layout Format Special Objects Object Lists Programs Sound Editing Sound Editing Music List Voices Sound Effects Level Data Formats Locations Models Model Files Animation Files Model Formats Info Level List Character Animation IDs Character Action Lists Event List Cutscenes Textures Global Indexes Sonic Adventure 2: Battle (Gamecube) Main Article Object Editing Editing Objects File Name Layout Format Special Objects Object Lists Programs Sound Editing Sound Editing Music List Voices Sound Effects Level Data Formats Locations Models Model Files Animation Files Model Formats Info Level List Character Animation IDs Character Action Lists Event List Cutscenes Textures Global Indexes Sonic Adventure 2 (PC) Main Article Object Editing Editing Objects File Name Layout Format Special Objects Object Lists Programs Sound Editing Sound Editing Music List Voices Sound Effects Level Data Formats Locations Models Model Files Animation Files Model Formats EXE Editing EXE Editing RAM Editing RAM Editing Info Level List Character Animation IDs Character Action Lists Event List Cutscenes Textures Global Indexes

The following is a breakdown of the model information used by all versions of Sonic Adventure 2.

Please make note of the version of the game that's being examined, as the byte order varies depending on the game and the file. The Dreamcast version of SA2 and the EXE/DLL of SA2 PC store their data in Little Endian, while SA2B and the rest of SA2 PC is in Big Endian.

The base addresses for models are as follows:
SA2 DC 1STREAD: 0x8C010000
SA2 DC STG Files: 0x8C500000
SA2 PC EXE: 0x402600
SA2 PC Data_DLL: 0x10002000

Chunk Model Format

ATTACH struct

Offset	Type	Description	Notes
0	Pointer	Vertlist
4	Pointer	Polylist
8	Float[3]	Model Center
14	Float	Radius

OBJECT struct

Offset	Type	Description	Notes
0	4 Bytes	Flags	See section below.
4	Pointer	Attach
8	Float[3]	Position
14	Int[3]	Rotation	Signed BAMS (0x10000 = 360°)
20	Float[3]	Scale	Ignored for level geometry.
2C	Pointer	OBJECT Child
30	Pointer	OBJECT Sibling

GC Model Format

ATTACH Struct

Offset	Type	Description	Notes
0	Pointer	Vertlist
4	4 Bytes	Unknown, tends to be null
8	Pointer	Opaque Polylist
C	Pointer	Alpha Polylist
10	Short	Opaque Poly Count
12	Short	Alpha Poly Count
14	Float[3]	Model Center
20	Float	Radius

OBJECT struct

Same as Chunk Model

OBJECT Flags

These flags have (or don't have) various effects on how the model data is used.

Bit	Value (hex)	Description
0	1	Don't apply position values. Seems to have no actual effect.
1	2	Don't apply rotation values. Seems to have no actual effect.
2	4	Don't apply scale values. Seems to have no actual effect.
3	8	Don't render this model. Does not affect level geometry.
4	10	Don't process children. Seems to have no actual effect.
5	20	Rotation values are in ZYX order. Seems to have no actual effect.
6	40	Don't include this model for animations.
7	80	Don't include this model for morphs.