AMS (File Format)

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AMS (Aqualead MeSh) is a file format developed by Aqualead and found in some Wii and 3DS games (and suspected to be used in GameCube titles as well), such as One Piece: Unlimited Adventure, One Piece: Unlimited Cruise Episode 1 - The Treasure Beneath The Waves, One Piece: Unlimited Cruise Episode 2: Awakening of a Hero, One Piece: Unlimited Cruise SP and One Piece: Unlimited Cruise SP 2.

File Format

The file byte order can be either big endian (Wii) or little endian (3DS).

Header

The file starts with the following header:

Offset	Type	Description
0x00	Char[4]	File magic. Always ALMS in ASCII.
0x04	Byte	Unknown. Format type or version? Values seen are 2, 3, 4, 5, 6, 7 and 8.
0x05	Byte	Unknown. Posibly bit flags, but files either use 0x80 or 0x81.
0x06	Byte	Number of materials (M).
0x07	Byte	Number of texture references (T).
0x08	Byte	Number of shapes (S).
0x09	Byte	Number of bones (B).
0x0A	Byte	Number of shape groups (G).
0x0B	Byte	Length of each material section in bytes.
0x0C	Float[3]	XYZ position of the model (does not apply to bones).
0x18	Float	Scale of the model (does not apply to bones).
0x1C	UInt16	Section 1 offset.
0x1E	UInt16	Section 2 offset.
0x20	UInt16	Section 3 offset.
0x22	UInt16	Section 4 offset.

Section 1

This section defines M material entries.

Material

Offset	Type	Description
0x00	Byte	Unknown.
0x01	Byte	Unknown.
0x02	Byte	Unknown.
0x03	Byte	Unknown. Always 0xB2?
0x04	Byte	Texture reference ID. 0xFF if none.
0x05	Byte	Unknown.
0x06	Byte	Unknown.
0x07	Byte	Unknown.
0x08	Byte	Unknown.
0x09	Byte	Unknown.
0x0A	Byte	Unknown.
0x0B	Byte	Unknown.

Section 2

This section defines T 0x4-byte texture references.

Texture Reference

Offset	Type	Description
0x00	Byte	Padding.
0x01	UInt24	Asset link identifier of the texture.

Section 3

This section defines B bone entries.

Bone

Offset	Type	Description
If format = 7
0x00	Char[4]	Bone name/ID. Hardcoded to be 4 characters long.
Else
0x00	float[3]	XYZ position.
0x0C	Char[4]	Bone name/ID. Hardcoded to be 4 characters long.
0x10	float[4]	Rotation, using quaternions.
0x20	float[4]	Unknown.

Section 4

This section defines S * G shape entries.

Offset	Type	Description
0x00	Int32[S]	Shape offsets.

Shape Header

Each shape starts with a 0x20 byte header.

Offset	Type	Description
0x00	Byte	Material ID.
0x01	Byte	Unknown.
0x02	Byte	Flag: xxxA xxxB. A: Unknown (sets some value to 32) B: Unknown. 4 floats come after the end of the header.
0x03	Byte	Unknown. Always 3?
0x04	UInt16	Number of Unknown Data 1 (S?).
0x06	5 bits	Unknown. Has something to do with the format of the vertex data.
0x06.5	3 bits	Number of vertex position sections. Each section corresponds to one section data helper for the vertex positions' index data.
0x07	4 bits	Vertex position data bytes per index in the draw commands: 0: Data not used; skip 2: 2 bytes (UInt16) Anything else: 1 byte
0x07.4	4 bits	Vertex position format. ID Description 0 Byte 1 SByte 2 UInt16 3 Int16 4 Float
0x08	UInt16	Number of vertex positions (SP).
0x0A	5 bits	Unknown. Has something to do with the format of the normal data.
0x0A.5	3 bits	Number of normal sections. Each section corresponds to one section data helper for the normals' index data.
0x0B	4 bits	Normal data bytes per index in the draw commands: 0: Data not used; skip 2: 2 bytes (UInt16) Anything else: 1 byte
0x0B.4	4 bits	Vertex normal format. ID Description 0 Byte 1 SByte 2 UInt16 3 Int16 4 Float
0x0C	UInt16	Number of vertex normals (SN). Normal data is usually always attached to the vertex data, so it's the same as the number of vertices (?)
0x0E	5 bits	Unknown. Has something to do with the format of the color data.
0x0E.5	3 bits	Number of color sections. Each section corresponds to one section data helper for the colors' index data.
0x0F	4 bits	Color data bytes per index in the draw commands: 0: Data not used; skip 2: 2 bytes (UInt16) Anything else: 1 byte
0x0F.4	4 bits	Vertex color format. ID Description 0 RGBA8 1 RGB8 2 RGBX8 3 RGBA4 4 RGBA6 5 RGB565
0x10	UInt16	Number of vertex colors (SC).
0x12	5 bits	Unknown. Has something to do with the format of the UV data.
0x12.5	3 bits	Number of UV sections. Each section corresponds to one section data helper for the UVs' index data.
0x13	4 bits	UV data bytes per index in the draw commands: 0: Data not used; skip 2: 2 bytes (UInt16) Anything else: 1 byte
0x13.4	4 bits	UV format. ID Description 0 Byte 1 SByte 2 UInt16 3 Int16 4 Float
0x14	UInt16	Number of UVs (SU).
0x16	5 bits	Unknown. Has something to do with the format of the bone ID data.
0x16.5	3 bits	Number of bone ID sections. Each section corresponds to one section data helper for the bone ID data.
0x17	4 bits	Unknown. This value would correspond to the bone ID data bytes per index, but instead each entry corresponds to a vertex position. If bones are used, this value is always 1 (?)
0x17.4	4 bits	Bone ID format. ID Description 0 Byte 1 SByte 2 UInt16 3 Int16 4 Float
0x18	UInt16	Number of bone entries (SB).
0x1A	5 bits	Unknown. Has something to do with the format of the weight data.
0x1A.5	3 bits	Number of weight sections. Each section corresponds to one section data helper for the weight data.
0x1B	4 bits	Unknown. This value would correspond to the weight data bytes per index, but instead each entry corresponds to a vertex position. Always 0 (?)
0x1B.4	4 bits	Weight format. ID Description 0 Byte 1 SByte 2 UInt16 3 Int16 4 Float
0x1C	Byte[2]	Unknown.
0x1E	UInt16	Section Data Helpers offset. Usually 0x20 or 0x30. If the value is 0, the Section Data Helpers come either at 0x20 (if the last bit of the value at 0x2 from this header is 0) or at 0x30 (if the value is 1). This value is always aligned by 4 bytes.

Section Data Helpers

These entries seem to contain the offsets of the first instance for each of the entries defined in the Shape Header. Commonly, the first 4-byte entry is always related to the unit data, and the second one to its first draw command unit ID. For weight/bone data, it only has one entry, as they are not referenced by the draw commands. All offsets are relative to the start of the Shape Header.

Format of a section data helper

Offset	Type	Description
0x00	Byte	Stride of an entire entry unit in bytes.
0x01	UInt24	Data offset for the first instance of the entry. These offsets indicate the first entry for each entry type defined by the Shape Header, including overlapping entries that may share a common data array. For example, the vertex data array may contain normal and weight data attached to each vertex, but the entries for position, normal and weight data are separate. As for the offsets of the unit indices, it correlates to the specific part of the first draw command that references the entry type.

Unknown Data 1

This section follows directly after the Section Data Helpers and contains S? entries, seen in UInt16 format, unless specified somewhere in the Shape Header. The purpose of this section is unknown and it does not seem to be referenced by the Section Data Helpers.

Bone References

This section follows directly after the Unknown Data 1 and contains SB entries, seen in Byte format, unless specified somewhere else in the Shape Header. This section seems to list the indices of the bones in order. This section does not seem to be referenced by the Section Data Helpers.

Vertex Position Data

This section follows after the Bone References and contains SP entries; the format of each defined by the Section Header. Sometimes vertex positions, normals and weight/bone indices may be packed together in this section.

Vertex Normal Data

SN vertex normal entries seem to come after the Vertex Position Data, if present; the format of each defined by the Section Header.

Vertex Color Data

SC vertex color entries seem to come after the Vertex Normal Data, if present; the format of each defined by the Section Header.

UV Data

SU UV entries seem to come after the Color Data, if present; the format of each defined by the Section Header.

Draw Data

After the UV entries comes the Draw Data. This section starts with a 4-byte header:

Draw Data Header

Offset	Type	Description
0x00	Byte	Unknown. Always 0x80? Perhaps this value indicates that the data is made of Wii Graphics' commands.
0x01	UInt24	Length of the draw commands in bytes.

Directly after the header there are the Wii Draw Commands.

Unknown Data 2

After the Draw Data comes an Unknown Data section. It starts with a 2-byte header:

Unknown Data 2 Header

Offset	Type	Description
0x00	UInt16	Length of the data in bytes.

Directly after the header there is the unknown data.

Tools

The following tools can handle AMS files:

• (none)