Char [4] 'BIGB'
Char [4] Version
Int [4] Bank address
Int [4] unknown

Int [4] Number of Banks
Char [x] NULL terminted string
Int [4] Bank ID

Int [4] Number of Entries in Bank
Int [4] Index Start
Int [4] Index Size
Int [4] block size

Int [4] NumberFileTypes
Int [4] FileType
Int [4] NumberFiles

Int [4] Magic Number
Int [4] File ID
Int [4] File Type
Int [4] File Size
Int [4] File Start
–[dev info]–
Int [4] File Type
Int [4] StringLength;
Int [StringLength] SymbolName
Int [4] File CRC
Int [4] Number of Source Files
Int [4] StringLength;
Int [StringLength] Source File Name
–[/dev info]–
Int [4] SubHeaderSize
Int [SubHeaderSize] SubHeader

Int [2] Width; Texture size…
Int [2] Height;
Int [2] Depth; …and depth for vol. textures
Int [2] FrameWidth; Actual image size (may be smaller)
Int [2] FrameHeight;
Int [2] FrameCount;
Int [2] DXT Compression;
Int [2] Unkown;
Int [1] Transparency; Number of alpha channels
Int [1] MipMaps; Number of MipMaps
Int [2] Unkown;
Int [4] TopMipmapSize;
Int [4] TopMipmapCompressedSize;
Int [2] Unkown; DXT compression again?
Int [4] Unkown;

The first mipmap of each texture is compressed using lzo1x and the rest are uncompressed.

Dword Physics_Mesh;
Float [10]; matches first 40 bytes of bbm. possibly origin
Dword Number_LOD's;
Dword [Number_LOD's] Size_compressed_LOD;
Dword padding;
Dword Number_Textures_Assigned; 1 per surface within model
Dword [Number_Textures_Assigned] Texture_ID; Texture ID as used in the textures.big