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SCHG

Sonic Adventure/Model Format

From Sonic Retro

SCHG: Sonic Adventure
Dreamcast
Gamecube
PC
2010

Remember: all pointers are 4 Bytes, and need to have a key subtracted from them to find the correct location in a file.
For sonic.exe, subtract 0x00400000.
For DLL files, subtract 0x10000000.
For BIN files from the dreamcast version, subtract 0x0C900000.
For 1st_read.bin from the dreamcast version, subtract 0x8C010000.
Nothing is currently known about the Gamecube version.

Model Format

As a rule, data sets occur in the reverse order that these pointers do. In a non-hacked model, the model data always starts with the material structs and goes down the file to the vertex struct, with the exception of the vertex struct. The verts occur right after the mesh struct and the normals are the last data set before the attach struct. The tools sonic team used strictly followed that rule, but the game can operate outside of that constraint so make sure your pointers are always accurate. A crashing game usually means a bad pointer!
Note: these are listed in the order they will appear in the file. However, it is likely that you will start at the OBJECT Struct.

MATERIAL Struct

The game loads as many of these structs as indicated in the attach struct. The format is as follows.

offset Type Description Notes
0 4 Bytes Diffuse Color in 0xAARRGGBB format
4 4 Bytes Specular Color in 0xAARRGGBB format
8 Float Exponent
C 4 Bytes 28-bit Texture ID, 4 bits unused
10 4 Bytes Material flags

POLY Struct

Triangles

Three shorts, indicating the vertices to use.

Quads

Four shorts, indicating the vertices to use.

Strips

A byte indicating the number of strips to load, a byte indicating the direction to read the strips in, followed by an array of shorts indicating which vertices to use.

VColor Struct

An array of ints in 0xAARRGGBB format for each vertex in the strip.

UV Struct

An array of two shorts representing the U and V coordinates for each vertex in the strip.

MESH Struct

The game loads as many of these structs as indicated in the attach struct. The format is as follows.

offset Type Description Notes
0 2 Bytes Low 14 bits Material ID High 2 bits Poly Type: 0 = Triangles, 1 = Quads, 2 or 3 = Strips
2 2 Bytes Poly Total This is how many polys to load
4 Pointer Polys Read notes on poly data
8 Pointer Pattr Unused by sadx (maybe), but are part of official sega model format
C Pointer PolyNormal If it's non-zero, points to an array containing two Floats for each POLY.
10 Pointer Vertex Colors
14 Pointer UV Coordinates
18 4 Bytes Null Only in DX version.

VERTEX Struct

A Float[3] for each vertex, times the total specified in the ATTACH Struct.

ATTACH Struct

Offset Type Description Notes
0 Pointer Vertices
4 Pointer Normals
8 4 Bytes Vertex/Normal Total
C Pointer Meshes
10 Pointer Materials
14 2 Bytes Mesh Total
16 2 Bytes Material Total
18 Float[3] Center
24 Float Radius
28 4 Bytes Null Only in DX version.

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 Relate

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.

Model Editing Tutorial

(For SADXPC)

Disclaimer

"The information below on model editing is old, outdated, and generally a pain. It should be ignored, but for the moment I am way too lazy to give it an update proper. Look to the right for a list of much more useful, up-to-date, and pertinent information." - Dude

Alright, so you want to edit models in SADX.

First off you need to think of what character you want to edit.

Let's say you want to do Sonic. His head model is name group5674388.

The 5674388 is the decimal offset in CHRMODELS.DLL you need to go to. Use a calculator to convert this number to hexadecimal; in this case the value is 569594.

Open CHRMODELS.DLL in a hex editor. Open the "go to" window (usually done by pressing Ctrl+G). If your editor supports decimal you can just paste in the original value, or you can choose hexadecimal and use that number. Most models end in something like _4 or _20; you only need the numbers before the dash.

Once you have gone to the offset for Sonic's head, you will see 04 00 00 00 (or 0400 0000, depending on how your hex editor is set up; every 2 numbers/letters is one hex byte).

So you want to skip the first 4 bytes, in this case that is 04 00 00 00. You should now see 68 95 56 10 (or another value for a different model). These four bytes are the next offset you want to go to, but they are in little endian and have had 10000000 added to them. Reverse the order of the bytes and subtract 10000000 to get 00569568, and then go to this address.

This time we do NOT skip the first 4 bytes, we select the first 4 bytes which are 78 73 56 10 and once again, reverse the byte order and subtract 10000000. You should get 00567378.

Go to this offset. You are now at the model =D. what you need to do now, is export your edited model in .obj format. (When editing the model do not use symmetry modifiers or mirror the model! You must edit each vertex by hand, you can't mirror it)

Drop your .obj file on obj2vt.exe and you will get an out.vt. Open the out.vt in a hex editor and check how many bytes it has. Off the top of my head, I believe sonic has around 4,000 something. well, check how many bytes that has, and go back to CHRMODELS.DLL. Select a block, the same size as the other file and hit the delete key. Go back to out.vt and select everything and copy it. Paste it in CHRMODELS.DLL were you deleted the old model.

Save, and it should work.

Animation Format

Offset Type Description
0 Pointer Model (OBJECT Struct)
4 Pointer Section 2
Offset Type Description
0 Pointer Frame Data
4 4 Bytes Total frame count
8 2 Bytes Data flags
A 2 Bytes Number of pointer/frame count pairs

Flags:
0x1: Contains Position data
0x2: Contains Rotation data
0x4: Contains Scale data

The next section contains data in the following order, as the flags dictate:
Position Data pointer
Rotation Data pointer
Scale Data pointer
4 Byte Position Data frame count
4 Byte Rotation Data frame count
4 Byte Scale Data frame count

Position/Scale data:

Offset Type Description
0 4 Bytes Frame number
4 Float X
8 Float Y
C Float Z

Rotation data:

Offset Type Description
0 4 Bytes Frame number
4 4 Bytes X
8 4 Bytes Y
C 4 Bytes Z

If the position, rotation and scale data exist, they will override the values from the OBJECT Struct.

Character Node Hierarchy

The following is a list of the node hierarchies for each playable character in the game.

Sonic/Super Sonic/Metal Sonic

  • This list is based on observations when the model is viewed in SAMDL. As such, it's inaccurate for the time being.
ID Description
0 Root node
1
2
3
4
5
6
7
8
9
10 Chest
11 Face (Parent)
12 Face (Parent 2)
13
14 Right Eye (Parent)
15 Right Eye (Parent 2)
16
17 Right Eye
18 Left Eye (Parent)
19 Left Eye (Parent 2)
20
21 Left Eye
22 Head
23 Sclera
24 Right Arm (Parent)
25 Right Arm (Parent 2)
26 Right Bicep (Parent)
27 Right Elbow (Parent)
28
29 Right Wrist
30 Right Palm
31 Right Thumb
32 Right Fingers
33 Right Elbow
34 Right Bicep
35 Left Arm (Parent)
36 Left Arm (Parent 2)
37 Left Bicep (Parent)
38 Left Elbow (Parent)
39
40 Left Wrist
41 Left Palm
42 Left Thumb
43 Left Fingers
44 Left Elbow
45 Left Bicep
46 Right Leg (Parent)
47 Right Leg (Parent 2)
48 Right Thigh (Parent)
49 Right Knee (Parent)
50
51 Right Calf
52 Right Heel
53 Right Toe
54 Right Knee
55 Right Thigh
56 Left Leg (Parent)
57 Left Leg (Parent 2)
58 Left Thigh (Parent)
59 Left Knee (Parent)
60
61 Left Calf
62 Left Heel
63 Left Toe
64 Left Knee
65 Left Thigh
66 Tail (Parent)
67 Tail (Parent 2)
68
69 Tail
70
71
72

Tails

  • This list is based on observations when the model is viewed in SAMDL. As such, it's inaccurate for the time being.
ID Description
0 Root node
1
2
3
4 Face (Parent)
5
6
7 Head
8 Right Eye
9 Left Eye
10 Right Arm (Parent)
11
12
13
14
15 Right Wrist
16 Right Palm
17 Right Fingers
18 Right Thumb
19 Right Elbow
20 Right Bicep
21 Left Arm (Parent)
22
23
24
25
26 Left Wrist
27 Left Palm
28 Left Fingers
29 Left Thumb
30 Left Elbow
31 Left Bicep
32 Right Leg (Parent)
33
34
35
36
37 Right Calf
38 Right Heel
39 Right Toe
40 Right Knee
41 Right Thigh
42 Left Leg (Parent)
43
44
45
46
47 Left Calf
48 Left Heel
49 Left Toe
50 Left Knee
51 Left Thigh
52
53
54
55
56
57
58 Chest
59 Right Tail (Parent)
60
61
62 Right Tail
63 Left Tail (Parent)
64
65
66 Left Tail
67

Knuckles

  • This list is based on observations when the model is viewed in SAMDL. As such, it's inaccurate for the time being.
ID Description
0 Root node
1
2
3
4
5
6
7
8
9
10 Face (Parent)
11
12
13 Right Eye (Parent)
14
15
16 Right Eye
17 Left Eye (Parent)
18
19
20 Left Eye
21 Head
22 Sclera
23 Right Arm (Parent)
24
25
26
27
28 Right Wrist
29 Right Palm
30 Right Thumb
31 Right Fingers
32 Right Elbow
33 Right Bicep
34 Left Arm (Parent)
35
36
37
38
39 Left Wrist
40 Left Palm
41 Left Thumb
42 Left Fingers
43 Left Elbow
44 Left Bicep
45 Right Leg (Parent)
46
47
48
49
50 Right Calf
51 Right Heel
52 Right Toe
53 Right Knee
54 Right Thigh
55 Left Leg (Parent)
56
57
58
59
60 Left Calf
61 Left Heel
62 Left Toe
63 Left Knee
64 Left Thigh
65 Tail (Parent)
66
67
68 Tail
69
70
71
72 Chest

Amy

  • This list is based on observations when the model is viewed in SAMDL. As such, it's inaccurate for the time being.
ID Description
0 Root node
1
2
3
4
5
6
7
8
9
10 Face (Parent)
11
12
13 Right Eye (Parent)
14
15
16 Right Eye
17 Left Eye (Parent)
18
19
20 Left Eye
21 Head
22 Headband
23 Sclera
24 Left Eyelash
25 Right Eyelash
26 Right Arm (Parent)
27
28
29
30
31 Right Wrist
32 Right Palm
33 Right Thumb
34 Right Fingers
35 Hammer Handle
36 Hammer Head
37 Right Elbow
38 Right Bicep
39 Left Arm (Parent)
40
41
42
43
44 Left Wrist
45 Left Palm
46 Left Thumb
47 Left Fingers
48 Left Elbow
49 Left Bicep
50 Right Leg (Parent)
51
52
53
54
55 Right Calf
56 Right Heel
57 Right Toe
58 Right Knee
59 Right Thigh
60 Left Leg (Parent)
61
62
63
64
65 Left Calf
66 Left Heel
67 Left Toe
68 Left Knee
69 Left Thigh
70 Tail (Parent)
71
72
73 Tail
74
75
76
77 Chest

Big

  • This list is based on observations when the model is viewed in SAMDL. As such, it's inaccurate for the time being.
ID Description
0 Root node
1
2
3 Right Leg (Parent)
4
5
6
7 Right Heel
8 Right Toe
9 Right Calf
10 Right Thigh
11 Left Leg (Parent)
12
13
14
15 Left Calf
16 Left Heel
17 Left Toe
18 Left Thigh
19 Tail (Parent)
20
21
22 Tail
23 Stomach (Below the Belt)
24
25
26
27 Right Arm (Parent)
28
29
30
31
32 Right Wrist
33 Right Palm
34 Right Fingers
35 Right Thumb
36 Right Elbow
37 Right Bicep
38 Left Arm (Parent)
39
40
41
42
43 Left Palm
44 Left Fingers
45 Left Thumb
46 Fishing Rod
47 Fishing Rod Reel
48 Fishing Rod Reel Handle
49 Left Wrist
50 Left Elbow
51 Left Bicep
52
53
54
55
56
57
58 Face (Parent)
59
60
61 Jaw
62 Head
63 Right Eye
64 Left Eye
65 Right Iris
66 Left Iris
67 Right Whiskers
68 Left Whiskers
69
70 Chest
71 Belt Buckle
72 Loose Belt Flap

E-102 Gamma

  • This list is based on observations when the model is viewed in SAMDL. As such, it's inaccurate for the time being.
ID Description
0 Root node
1
2
3 Right Leg (Parent)
4
5
6
7
8 Right Calf
9 Right Leg Wheel Hub
10 Right Leg Wheel
11 Right Heel
12 Right Toe
13 Right Knee
14 Right Thigh
15 Left Leg (Parent)
16
17
18
19
20 Left Calf
21 Left Leg Wheel Hub
22 Left Leg Wheel
23 Left Heel
24 Left Toe
25 Left Knee
26 Left Thigh
27
28
29
30 Chest
31 Right Arm (Parent)
32
33
34
35
36 Gun
37 Gun Handle
38 Right Elbow
39 Right Bicep
40 Left Arm (Parent)
41
42
43
44
45 Left Wrist
46 Left Palm
47 Left Fingers
48 Left Thumb
49 Left Elbow
50 Left Bicep
51 Face (Parent)
52
53
54 Head
55 Left Eye
56 Right Eye with "nose" markings
57 Lower Chest
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73 Exhaust Belt
74 Metallic Flap
75 Headlight Base
76 Headlight
Sonic Community Hacking Guide
General
Sonic Music Hacking Guide | SonED2 Manual
Game-Specific
Sonic the Hedgehog (16-bit) | Sonic the Hedgehog (8-bit) | Sonic Eraser | Sonic CD (prototype 510) | Sonic CD | Sonic CD (PC) | Sonic CD (2011) | Sonic 2 (Nick Arcade prototype) | Sonic 2 (Simon Wai prototype) | Sonic 2 (16-bit) | Sonic 2 (8-bit) | Sonic 2 & Knuckles | Dr. Robotnik's Mean Bean Machine | Sonic Triple Trouble | Sonic 3 | Sonic & Knuckles | Sonic the Hedgehog 3 & Knuckles | Sonic & Knuckles Collection | Sonic Crackers | Sonic 3D: Flickies' Island | Chaotix | Sonic R PC | Sonic Jam 6 | Sonic Advance | Sonic Advance 2 | Sonic Advance 3 | Sonic Battle | Sonic Adventure | Sonic Adventure DX: Director's Cut | Sonic Adventure DX: PC | Sonic Adventure (2010) | Sonic Shuffle | Sonic Adventure 2 | Sonic Adventure 2: Battle | Sonic Adventure 2 (PC) | Sonic Heroes | Shadow the Hedgehog | Sonic Riders | Sonic the Hedgehog (2006) | Sonic & Sega All-Stars Racing | Sonic Unleashed (Xbox 360/PS3) | Sonic Colours | Sonic Generations | Sonic Lost World | Sonic Forces
Legacy Guides
The Nemesis Hacking Guides The Esrael Hacking Guides
ROM: Sonic 1 | Sonic 2 | Sonic 2 Beta | Sonic 3

Savestate: Sonic 1 | Sonic 2 Beta/Final | Sonic 3

Sonic 1 (English / Portuguese) | Sonic 2 Beta (English / Portuguese) | Sonic 2 and Knuckles (English / Portuguese)
Move to Sega Retro
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