NKM (File Format)

Introduction

NKM is a file format that describes objects, routes, cameras and other information about a course in Mario Kart DS and is the equivalent to Mario Kart Wii's KMP. The file is written in little endian.

Header

Offset	Size	Type	Description
0x00	0x04	String	File magic in ASCII (NKMD)
0x04	0x02	UInt16	Version number. Final tracks are always 3.7 (0x25 = 37). Beta tracks are 3.0 (0x1E = 30), 3.2 (0x20 = 32) or 3.4 (0x22 = 34). The files written with MKDS Course Modifier 4.0 beta 10 are 4.0 (0x28 = 40), because of the additional information section
0x06	0x02	UInt16	Header length
0x08	Header Length - 0x08	UInt32[]	Section offsets. Not always the same amount. Some beta tracks are missing some sections

Typical Header

A typical header is 0x4C long and has 17 sections.

Offset	Size	Type	Description
0x00	0x04	String	File magic in ASCII (NKMD)
0x04	0x02	UInt16	Version number
0x06	0x02	UInt16	Header length
0x08	0x04	UInt32	OBJI section offset
0x0C	0x04	UInt32	PATH section offset
0x10	0x04	UInt32	POIT section offset
0x14	0x04	UInt32	STAG section offset
0x18	0x04	UInt32	KTPS section offset
0x1C	0x04	UInt32	KTPJ section offset
0x20	0x04	UInt32	KTP2 section offset
0x24	0x04	UInt32	KTPC section offset
0x28	0x04	UInt32	KTPM section offset
0x2C	0x04	UInt32	CPOI section offset
0x30	0x04	UInt32	CPAT section offset
0x34	0x04	UInt32	IPOI section offset
0x38	0x04	UInt32	IPAT section offset
0x3C	0x04	UInt32	EPOI section offset
0x40	0x04	UInt32	EPAT section offset
0x44	0x04	UInt32	AREA section offset
0x48	0x04	UInt32	CAME section offset

Sections

Section Header

Every sections except the STAG section starts with the section header. The section header is a 0x08 byte structure as follows.

Offset	Size	Type	Description
0x00	0x04	String	Section magic in ASCII
0x04	0x04	UInt32	Number of entries in section

OBJI

The OBJI Section describes object used in tracks. Each entry is a 0x3C byte structure as follows.

Offset	Size	Type	Description
0x00	0x0C	Vector	3D position vector
0x0C	0x0C	Vector	3D rotation vector
0x18	0x0C	Vector	3D scale vector
0x24	0x20	UInt16	Object ID
0x26	0x02	UInt16	Route ID
0x28	0x04	UInt32	Object setting 1
0x2C	0x04	UInt32	Object setting 2
0x30	0x04	UInt32	Object setting 3
0x34	0x04	UInt32	Object setting 4
0x38	0x04	UInt32	Show in Time Trails. 1 if shown, 0 if not

PATH

The PATH section describes paths used for objects and cameras. Each entry is a 0x04 byte structure as follows.

Offset	Size	Type	Description
0x00	0x01	Byte	Route ID
0x01	0x01	Byte	1 if the route loops, 0 otherwise
0x02	0x02	UInt16	Nr points. The points are in the POIT section

POIT

The POIT section describes points that is used by the PATH section. Each entry is a 0x14 byte structure as follows.

Offset	Size	Type	Description
0x00	0x0C	Vector	3D position vector
0x0C	0x02	Int16	Point index in the Route
0x0E	0x02	Int16	Point duration. Not always used
0x10	0x04	UInt32	Unknown

STAG

The STAG section describes global information about the track. It doesn't use the section header. The section is a 0x2C byte structure as follows.

Offset	Size	Type	Description
0x00	0x04	String	Section magic in ASCII (STAG)
0x04	0x02	UInt16	Track ID
0x06	0x02	UInt16	Amount of laps
0x08	0x0C	Byte[12]	Unknown 1
0x14	0x04	UInt32	Fog distance
0x18	0x02	GXRgb	Fog color
0x1A	0x02	UInt16	Fog alpha (0-15)
0x1C	0x02	GXRgb	KCL color 1, the default color
0x1E	0x02	GXRgb	KCL color 2
0x20	0x02	GXRgb	KCL color 3
0x22	0x02	GXRgb	KCL color 4
0x24	0x08	Byte[8]	Unknown 2

KTPS

The KTPS section describes start positions of racers. Each entry is a 0x1C byte structure as follows.

Offset	Size	Type	Description
0x00	0x0C	Vector	3D position vector
0x0C	0x0C	Vector	3D rotation vector
0x18	0x02	UInt16	Padding (0xFFFF)
0x1A	0x02	Int16	Start position index. Only used in battle stages and mission mode. For regular courses it is -1

KTPJ

The KTPJ section describes respawn positions. Each entry is a 0x20 byte structure as follows.

Offset	Size	Type	Description
0x00	0x0C	Vector	3D position vector
0x0C	0x0C	Vector	3D rotation vector
0x18	0x02	Int16	Enemy position ID (EPOI)
0x1A	0x02	Int16	Item position ID (IPOI)
0x1C	0x04	Int32	Respawn ID

KTP2

The KTP2 section describes points you need to pass to let the lap count. Each entry is a 0x1C byte structure as follows.

Offset	Size	Type	Description
0x00	0x0C	Vector	3D position vector
0x0C	0x0C	Vector	3D rotation vector
0x18	0x02	UInt16	Padding (0xFFFF)
0x1A	0x02	Int16	Index. Always -1, because it's not used in battle stages. (If more than one works, it could be another value)

KTPC

The KTPC section describes cannons (or pipe) destination points. Pipes do only work in battle mode by default. Each entry is a 0x1C byte structure as follows.

Offset	Size	Type	Description
0x00	0x0C	Vector	3D position vector
0x0C	0x0C	Vector	3D rotation vector
0x18	0x02	UInt16	Unknown
0x1A	0x02	Int16	Cannon index. Used for the 'Cannon Activator' collision type

KTPM

The KTPM sections describes points that you need to pass to let a mission succeed. Each entry is a 0x1C byte structure as follows.

Offset	Size	Type	Description
0x00	0x0C	Vector	3D position vector
0x0C	0x0C	Vector	3D rotation vector
0x18	0x02	UInt16	Padding (0xFFFF)
0x1A	0x02	Int16	Index (last start position index + 1 is the first one)

CPOI

The CPOI section describes check points. Each entry is a 0x24 byte structure as follows.

Offset	Size	Type	Description
0x00	0x04	Vector	2D position vector
0x08	0x04	Vector	2D position vector
0x10	0x04	float	Sinus, it's sign has to be reversed sometimes
0x14	0x04	float	Cosinus, it's sign has to be reversed sometimes
0x18	0x04	float	Distance
0x1C	0x02	Int16	Section data 1. Has to do with different sections and such, but it is still very unknown
0x1E	0x02	Int16	Section data 2. Has to do with different sections and such, but it is still very unknown
0x20	0x02	Int16	Keypoint ID. -1 if it is no key point
0x22	0x01	Byte	Respawn ID
0x23	0x01	Byte	Unknown

CPAT

The CPAT section describes CPOI grouping. Each entry is a 0x0C byte structure as follows.

Offset	Size	Type	Description
0x00	0x02	UInt16	Point start
0x02	0x02	UInt16	Point length
0x04	0x03	SByte[3]	Next group. The indicies of up to 3 the previous CPOI groups entries may have followed. Unneeded slots are set to value -1
0x07	0x03	SByte[3]	Previous group. The indicies of up to 3 next CPOI group entries to follow. Unneeded slots are set to value -1
0x0A	0x02	Int16	Section order

IPOI

The IPOI section describes item points; the routes of items such as red shells. Each entry is a 0x14 byte structure as follows.

Offset	Size	Type	Description
0x00	0x0C	Vector	3D position vector
0x0C	0x04	float	Point scale
0x10	0x04	UInt32	Unknown

IPAT

The IPAT section describes IPOI grouping. Each entry is a 0x0C byte structure as follows.

Offset	Size	Type	Description
0x00	0x02	UInt16	Point start
0x02	0x02	UInt16	Point length
0x04	0x03	SByte[3]	Next group. The indicies of up to 3 the previous IPOI groups entries may have followed. Unneeded slots are set to value -1
0x07	0x03	SByte[3]	Previous group. The indicies of up to 3 next IPOI group entries to follow. Unneeded slots are set to value -1
0x0A	0x02	Int16	Section order

EPOI

The EPOI section describes enemy points; the routes that the CPUs take. Each entry is a 0x18 byte structure as follows.

Offset	Size	Type	Description
0x00	0x0C	Vector	3D position vector
0x0C	0x04	float	Point scale
0x10	0x02	Int16	Drifting
0x12	0x02	UInt16	Unknown
0x14	0x04	UInt32	Unknown

EPAT

The EPAT section describes EPOI grouping. Each entry is a 0x0C byte structure as follows.

Offset	Size	Type	Description
0x00	0x02	UInt16	Point start
0x02	0x02	UInt16	Point length
0x04	0x03	SByte[3]	Next group. The indicies of up to 3 the previous EPOI groups entries may have followed. Unneeded slots are set to value -1
0x07	0x03	SByte[3]	Previous group. The indicies of up to 3 next EPOI group entries to follow. Unneeded slots are set to value -1
0x0A	0x02	Int16	Section order

MEPO

The MEPO section describes minigame enemey points. Each entry is a 0x16 byte structure as follows.

Offset	Size	Type	Description
0x00	0x0C	Vector	3D position vector
0x0C	0x04	float	Point scale
0x10	0x02	Int16	Drifting
0x12	0x04	UInt32	Unknown

MEPA

The MEPA section describes MEPO grouping. Each entry is a 0x0C byte structure as follows.

Offset	Size	Type	Description
0x00	0x02	UInt16	Point start
0x02	0x02	UInt16	Point length
0x04	0x03	SByte[8]	Next group. The indicies of up to 8 the previous MEPO groups entries may have followed. Unneeded slots are set to value -1
0x07	0x03	SByte[8]	Previous group. The indicies of up to 8 next MEPO group entries to follow. Unneeded slots are set to value -1

AREA

The AREA section describes areas, mosty used for determine which camera to use. Each entry is a 0x48 byte structure as follows.

Offset	Size	Type	Description
0x00	0x0C	Vector	3D position vector
0x0C	0x0C	Vector	3D length vector
0x18	0x0C	Vector	X-vector?
0x24	0x0C	Vector	Y-vector?
0x30	0x0C	Vector	Z-vector?
0x3C	0x02	Int16	Unknown
0x3E	0x02	Int16	Unknown
0x40	0x02	Int16	Unknown
0x42	0x01	Byte	Unknown
0x43	0x01	SByte	Camera ID
0x44	0x01	Byte	Area type
0x45	0x02	UInt16	Unknown
0x47	0x01	Byte	Unknown

CAME

The CAME section describes cameras used in tracks. Each entry is a 0x4C byte structure as follows.

Offset	Size	Type	Description
0x00	0x0C	Vector	3D position vector 1
0x0C	0x0C	Vector	3D rotation vector
0x18	0x0C	Vector	3D position vector 2
0x24	0x0C	Vector	3D position vector 3
0x30	0x04	UInt32	Unknown
0x34	0x04	UInt32	Unknown
0x38	0x04	UInt32	Unknown
0x3C	0x02	Int16	Camera zoom
0x3E	0x02	Int16	Camera type Value Description 0x00 After race camera 0x01 ? (with route) 0x02 ? 0x03 Intro camera (top screen) 0x04 Intro camera (bottom screen) 0x05 ? 0x06 ? 0x07 Battle mode camera 0x08 Mission finish camera
0x40	0x02	Int16	Linked route (-1 if none)
0x42	0x02	Int16	Route speed
0x44	0x02	Int16	Point speed
0x46	0x02	Int16	Camera duration in 1/60 second units
0x48	0x02	Int16	Next camera (-1 if this is the last one)
0x4A	0x01	Byte	Intro pan first camera indicator (0x00 = none, 0x01 = top screen, 0x02 = bottom screen)
0x4B	0x01	Byte	Unknown (1 if camera type = 5)

Special (additional) Sections

Since MKDS Course Modifier 4.0 beta 10, some additional information may be stored in the NKM file.

NKMI

The NKMI section describes some information about the track itself, like the name and the version etc. It doesn't use the section header. This section is never present in the header. This is because of compatibility reasons. (MKDS doesn't know that this section exists). StringNT means a null terminated string.

Offset	Size	Type	Description
0x00	0x04	String	Section magic in ASCII (NKMI)
0x04	0x04	UInt32	Section length
0x08	a	StringNT	Track name
0x08 + a	b	StringNT	Author
0x08 + a + b	c	StringNT	Version
0x08 + a + b + c	d	StringNT	Last edit date. Format: dd/MM/yyyy HH:mm:ss (15/05/2013 16:18:04)

Tools

The following tools can handle Mario Kart DS NKM files:

• Every File Explorer, by Gericom
• MKDS Course Modifier, by Gericom