CMDL (Tropical Freeze)

See CMDL (File Format) for the other revisions of this format.

Tropical Freeze features a new model format (necessitated by the hardware jump from Wii to Wii U) that bears little-to-no resemblance to the CMDL format of past games. There are three extensions used for models:

• CMDL: Generic models
• SMDL: Skinned models (ie. animated characters)
• WMDL: World models (ie. level geometry)

All three share the same basic format, with SMDL and WMDL each containing an extra data chunk at the start of the file.

This file format needs more research There's still a lot of unknown data. The entire optional section at the end of HEAD is completely unknown to me and there's lots of scattered unknown values.

Format

After the RFRM Header, the first section of the file is SKHD in SMDL, and WDHD in WMDL. Following those extra sections, all three formats start with a header.

Model Header

Offset	Size	Description
0x0	24	"HEAD" Chunk Descriptor
0x18	4	Unknown
0x1C	4	Unknown
0x20	4	Unknown
0x24	4	Unknown
0x28	4	Unknown
0x2C	24	Axis-aligned bounding box
0x30	4	Extra data flag

If the ending flag is 1, then a large chunk of extra data follows before the next section begins; otherwise, the HEAD section ends.

Skinned Model Header

Offset	Type	Count	Name	Notes
0x0	Chunk Descriptor	1	SKHD Chunk Descriptor	Data type is SKHD
0x18	u32	1	Unknown
0x1C	End of Skinned Model Header

World Model Header

Type	Count	Name	Notes
u8	1	Unknown
Render Octree	1	Render Octree
u32	1	Unknown AABox Count
AABox	Unknown AABox Count	Unknown AABox Array
u32	1	Unknown Float Count
float	Unknown Float Count	Unknown Float Array

Render Octree

This seems to be an updated version of the AROT format seen in previous Retro games.

Offset	Type	Count	Name	Notes
0x0	FourCC	1	Magic	Always AROT (Area Octree)
0x4	u32	1	Unknown	Always 1. Version number?
0x8	u32	1	Unknown
0xC	u32	1	Unknown
0x10	u32	1	Unknown
0x14	AABox	1	Octree Bounding Box	Bounds of the entire octree; matches the bounding box from the main model header.
0x2C	u32	1	Unknown Count A
0x30	u32	Unknown Count A	Unknown Array A
	u32	1	Unknown Count B
	u8	Unknown Count B	Unknown Array B
	u32	1	Unknown AABox Count
	AABox	Unknown AABox Count	Unknown AABox Array

Material Data

The MTRL section has a 32-bit material count, then lays out its materials one after the other. Materials are composed of basically a MTRL asset ID which contains the shader the material is rendered with, then per-instance material parameters (textures, scalar/color parameters, etc).

Type	Count	Name	Notes
string	1	Material Name	Zero-terminated string
Asset ID (MTRL)	1	Material Shader Asset ID	Points to the MTRL file containing the shader for this material.
FourCC	1	Material Type	Can be PHNG (Phong), LAMB (Lambert), SURF (Surface), FURM (Fur), or REFL (Reflect). REFL may be unused.
u32	1	Material Flags	Bitfield used to toggle various settings on the material. None of the flags are known.
u32	1	Parameter Count	Count of parameters in this material definition.
Material Parameter	Parameter Count	Parameter Array

Material Parameter

Each parameter has a fourCC parameter ID as well as a parameter type enum. There are five possible parameter types that each have a different layout in the file.

Offset	Type	Count	Name	Notes
0x0	FourCC	1	Parameter ID
0x4	u32	1	Parameter Type	Determines what type of data this parameter contains. Can be either 0, 1, 2, 4, or 5. (Note: 3 is an invalid value, not an unused type.)
0x8			Parameter Data	Structure and size varies depending on Parameter Type. See below.

Type 0: Texture Token Data

Offset	Type	Count	Name	Notes
0x0	Asset ID (TXTR)	1	Texture ID	Texture asset ID.
0x10	Texture Usage Info	1	Texture Usage Info	Note: Not present if the TXTR asset ID is invalid.
End of Texture Token Data

Type 1: Color Data

Offset	Type	Count	Name	Notes
0x0	Color4f	1	Color Value
0x10	End of Color Data

Type 2: Scalar Data

Offset	Type	Count	Name	Notes
0x0	float	1	Scalar Value
0x4	End of Scalar Data

Type 4: Layered Texture Data

Offset	Type	Count	Name	Notes
0x0	u32	1	Unknown
0x4	Color4f	1	Unknown Color
0x14	Color4f	1	Unknown Color
0x24	Color4f	1	Unknown Color
0x34	u8	1	Unknown
0x35	Texture Token Data	1	Unknown Texture Token Data
	Texture Token Data	1	Unknown Texture Token Data
	Texture Token Data	1	Unknown Texture Token Data
End of Layered Texture Data

Type 5: Int4 Data

Offset	Type	Count	Name	Notes
0x0	u32	4	Int4 Value
0x10	End of Int4 Data

Texture Usage Info

Offset	Type	Count	Name	Notes
0x0	u32	1	Unknown
0x4	u32	1	Unknown
0x8	u32	1	Unknown
0xC	u32	1	Unknown
0x10	u32	1	Unknown
0x14	End of Texture Usage Info

Meshes

The MESH section does what the name suggests: it defines submeshes. The MESH section header is as follows:

Offset	Size	Description
0x0	24	MESH Chunk Descriptor
0x18	4	Submesh count
0x1C	End of MESH header

Each submesh definition is structured as follows:

Offset	Size	Description
0x0	4	Unknown; always 3?
0x4	2	Material ID
0x6	1	Vertex buffer ID
0x7	1	Index buffer ID
0x8	4	Start index
0xC	4	Index count
0x10	4	Unknown
0x14	1	Unknown; usually seems to be either 0 or 1, possibly a bool value
0x15	End of submesh definition

Vertex Buffers

The VBUF section defines vertex buffers; each buffer can have different vertex types, with different strides and attributes.

Header

Offset	Size	Description
0x0	24	VBUF Chunk Descriptor
0x18	4	Vertex buffer count
0x1C	End of VBUF header

Vertex Buffer

Offset	Size	Description
0x0	4	Vertex count
0x4	4	Attrib count (AC)
0x8	0x14 × AC	Vertex attributes
End of vertex buffer

Vertex Attribute

Offset	Size	Description
0x0	4	Unknown
0x4	4	Offset
0x8	4	Stride
0xC	4	Unknown
0x10	4	Unknown (likely attrib type/format)
0x14	End of attribute

Index Buffers

Just like how the VBUF section defines vertex buffers, the IBUF section defines index buffers. Each index buffer only has one value associated with it, so it's fairly simple, and you generally will only see one or two index buffers per file.

Header

Offset	Size	Description
0x0	24	IBUF Chunk Descriptor
0x18	4	Index buffer count
0x1C	End of IBUF header

Index Buffer

Offset	Size	Description
0x0	4	Format (1 means unsigned short; 2 means unsigned long)
0x4	End of index buffer

GPU Data

The GPU section contains raw buffer data that's fed to the GPU. It's essentially just a giant blob with all the vertex and index buffers laid out next to each other. The tricky part is, all the buffer data is LZSS-compressed, and the metadata needed to decompress it is stored in the pak rather than in the files themselves; not only that, but that metadata is also the only way to distinguish the different buffers from each other.

As such, this section can't be read correctly if the model file is unpacked and completely left as-is; it needs to be either read directly from the pak, or the metadata needs to be added to the file in some way. A good unpacker should append the metadata to the end of the file; a pre-decompressed file needs the buffer sizes or offsets inserted into the file data somewhere.

PAK Metadata

The pak metadata for the model formats contains mainly information related to the size and layout of the GPU section, and the metadata required to locate and decompress specific buffers within it.

Offset	Size	Description
0x0	4	Unknown; always 4?
0x4	4	GPU section offset
0x8	4	GPU chunk count (CC)
0xC	8 × CC	GPU chunk definitions
-	4	Compressed vertex buffer count (VC)
-	0x10 × VC	Vertex buffer definitions
-	4	Compressed index buffer count (IC)
-	0x10 × IC	Index buffer definitions
End of pak metadata

GPU Chunk

For large models, the GPU section might be split up into multiple chunks, rather than read as one data buffer; all offsets into the GPU section will be relative to the start of the chosen chunk.

Offset	Size	Description
0x0	4	Size
0x4	4	Offset
0x8	End of GPU chunk definition

Compressed Buffer

The format for compressed buffer definitions is the same regardless of buffer type (vertex/index).

Offset	Size	Description
0x0	4	GPU chunk index
0x4	4	Start offset (relative to the start of the chosen GPU chunk)
0x8	4	Compressed size
0xC	4	Decompressed size
0x10	End of compressed buffer definition