Sims 3:0x025ED6F4

By Karybdis:-

Its not just an XML, although versions 8+ may contain embedded XML files. Still missing versions lower than 12 (which are more or less this spec minus alot of parts)

These resources usually assemble the mesh parts of a whole sim.

DWORD version
DWORD TGI offset
DWORD count1
--repeat(count1)
	//Embedded XML
	DWORD length
	char16[length]
	if (version > 0x0000000E)
	{
		BYTE
	}
if (version > 0x0000000C)
{
	DWORD
	DWORD
}
FLOAT
FLOAT
FLOAT
DWORD
DWORD
12 BYTES
BYTE TGI index //Skin Type (0x0354796A)
if (version > 0x0000000C)
{
	FLOAT
}
DWORD //RGBA Color
DWORD //RGBA Color
DWORD //RGBA Color
BYTE count2
BYTE
--repeat(count2)
	if (version > 0x0000000C)
	{
		DWORD
	}
	BYTE count
	--repeat(count)
		BYTE TGI index // Property Set(0x033A1435)
		BYTE TGI index // Property Set(0x033A1435)
	BYTE TGI index // Body Part(0x034AEECB)
BYTE count3
--repeat(count3)
	DWORD TGI index //Face Part (0x0358B08A)
	DWORD flags
	FLOAT
BYTE count4
--repeat(count4)
	//TGI64
	QWORD instance
	DWORD group
	DWORD type

By Atavera:-

Flags for the CAS parts:

Type
[0x00000001] = Hair
[0x00000002] = Scalp
[0x00000004] = Face Overlay
[0x00000008] = Body
[0x00000010] = Accessory

Age/gender
[0x00000001] = Baby
[0x00000002] = Toddler
[0x00000004] = Child
[0x00000008] = Teen
[0x00000010] = Young Adult
[0x00000020] = Adult
[0x00000040] = Elder
[0x00001000] = Male
[0x00002000] = Female