BOL (File Format)

A BOL file contains information about a course's setup. A variant of the BOL format has been used in Mario Kart DS and Mario Kart Wii. This article describes the Mario Kart: Double Dash!! BOL format.

File Header

File header of a BOL file

Offset	Type	Description
0x00	String	File magic. Always 0015 in ASCII.
0x04	Byte	Seems to be related to moving collision. The value is set to 1 in daisy_course.bol. When this value is set to 0x00, the tables and rolling ? blocks on the cruiser will not move.
0x05	Byte[3]	Forms an RGB Ambient Color. All 3 values are set to 0x64 if 0.
0x08	Byte[4]	Forms an RGBA Light Color. All 4 values are set to 0xFF if 0.
0x0C	Float[3]	Light source position.
0x18	Byte	Number of laps.
0x19	Byte	Music ID.
0x1A	UInt16	Number of Section 1 entries.
0x1C	UInt16	Number of Section 2 groups.
0x1E	UInt16	Number of Section 5 entries.
0x20	UInt16	Number of Section 7 entries.
0x22	UInt16	Number of Section 8 entries
0x24	UInt16	Number of Section 3 entries.
0x26	UInt16	Number of Section 9 entries.
0x28	Byte	Fog Type.
0x29	Byte[3]	Fog Color.
0x2C	Float	Fog Start Z.
0x30	Float	Fog End Z.
0x34	UInt16	Unknown.
0x36	Byte	Unknown.
0x37	Byte	Unknown.
0x38	Byte[3]	Forms an RGB Shadow Color.
0x3B	Byte	Unknown. Start point related.
0x3C	Byte	Unknown.
0x3D	Byte	Number of Section 10 entries.
0x3E	Byte	Number of Section 11 entries. Should be 0x08 for battle courses.
0x3F	Byte	Unknown.
0x40	UInt32	Start of the file, always 0x00.
0x44	UInt32	Section 1 offset, always 0x7C.
0x48	UInt32	Section 2 offset.
0x4C	UInt32	Section 3 offset.
0x50	UInt32	Section 4 offset.
0x54	UInt32	Section 5 offset.
0x58	UInt32	Section 6 offset.
0x5C	UInt32	Section 7 offset.
0x60	UInt32	Section 8 offset.
0x64	UInt32	Section 9 offset.
0x68	UInt32	Section 10 offset.
0x6C	UInt32	Section 11 offset.
0x70	Byte[12]	Padding.
0x7C	End of this file header

Sections

The file consists of a series of sections, each describing a different aspect of the course setup.

Section 1

Section 1 describes enemy/item points; the routes of CPU racers and items such as red shells. The CPU racers and items attempt to follow the path described by each group of points. Each entry is a 0x20 byte structure as follows:

Offset	Type	Description
0x00	Float[3]	A 3D position vector of the position.
0x0C	Int16	Point setting.
0x0E	Int16	Link of current group if start of group. Link to next group if end of group. Otherwise -1.
0x10	Float	Scale.
0x14	UInt16	Group setting if start of group. Otherwise 0. 0: Enemy and items can enter group. 1: Items can enter group.
0x16	Byte	Group.
0x17	Byte	Point setting.
0x18	Byte	Unknown.
0x19	Int16	Unknown.
0x1B	Byte[5]	Padding.

Section 2

The first part of Section 2 describes checkpoint grouping; how the routes of checkpoints link together. Each entry is a 0x14 byte structure as follows:

Groups

Offset	Type	Description
0x00	UInt16	Point length. The number of points in this group.
0x02	UInt16	Group link.
0x04	Int16[4]	Previous group. The indices of up to 4 group links that follow to this one. Unneeded slots are set to value -1.
0x0C	Int16[4]	Next group. The indices of up to 4 group links to follow after this one. Unneeded slots are set to value -1.

The second part of Section 2 describes checkpoints; the routes players must follow to count laps. The racers must follow the path described by each group of points (as determined by the first part of Section 2). Each entry is a 0x1C byte structure as follows:

Points

Offset	Type	Description
0x00	Float[3]	A 3D position vector of the start of the check point line.
0x0C	Float[3]	A 3D position vector of the end of check point line.
0x18	Byte[4]	Padding.

Section 3

Section 3 describes routes; these are routes for many things including cameras and objects. Each entry is a 0x10 byte structure as follows:

Offset	Type	Description
0x00	UInt16	Point length. The number of Section 4 entries in this group.
0x02	UInt16	Point start. The index of the first Section 4 entry in this group.
0x04	Byte[12]	Padding.

Section 4

Section 4 describes route points. Each entry is a 0x20 byte structure as follows:

Offset	Type	Description
0x00	Float[3]	A 3D position vector of the route position.
0x0C	Byte[20]	Padding.

Section 5

Section 5 decribes objects. Each entry is a 0x40 byte structure as follows:

Offset	Type	Description
0x00	Float[3]	A 3D position vector of the object.
0x0C	Float[3]	A 3D scale vector of the object.
0x18	Int32[3]	A 3D rotation vector of the object.
0x24	UInt16	Object ID.
0x26	Int16	Route ID. Links to Section 3. 0xFFFF if no route is used.
0x28	Int32	Unknown.
0x2C	Byte	Unknown.
0x2D	Byte	Unknown.
0x2E	UInt16	Unknown.
0x30	UInt16	Unknown.
0x32	UInt16	Unknown.
0x34	UInt16	Unknown.
0x36	UInt16	Unknown.
0x38	UInt16	Unknown.
0x3A	UInt16	Unknown.
0x3C	UInt16	Unknown.

Section 6

Section 6 describes kart points; the starting positions of racers. Each entry is a 0x28 byte structure as follows:

Offset	Type	Description
0x00	Float[3]	A 3D position vector of the start position.
0x0C	Float[3]	A 3D scale vector of the start position.
0x18	Int32[3]	A 3D rotation vector of the start position.
0x24	Byte	0: Pole position is left 1: Pole position is right.
0x25	Byte	Player ID. In courses with multiple start positions (such as battle courses), this determines which players start here. Otherwise set to 0xFF to set all players start positions to this point.
0x26	UInt16	Padding.

Section 7

Section 7 describes areas; used to determine for example which camera to use. Each entry is a 0x38 byte structure as follows:

Offset	Type	Description
0x00	Float[3]	A 3D position vector of the area.
0x0C	Float[3]	A 3D scale vector of the area.
0x18	Int32[3]	A 3D rotation vector of the area.
0x24	UInt16	Area Type.
0x26	Int16	Index into Section 8 only if Area Type is 0x01. Otherwise, -1.
0x28	Byte[12]	Unknown.
0x34	UInt16	Shadow ID.
0x36	UInt16	Index into Section 10.

Section 8

Section 8 describes Cameras. Each entry is a 0x48 byte structure as follows:

Offset	Type	Description
0x00	Float[3]	A 3D position vector of the first view point.
0x0C	Int32[3]	A 3D rotation vector.
0x18	Float[3]	A 3D position vector of the second view point.
0x24	Float[3]	A 3D position vector of the third view point.
0x30	Byte	Unknown.
0x31	Byte	Camera Type.
0x32	UInt16	Start Zoom.
0x34	UInt16	Camera Duration (in 1/60 second units).
0x36	UInt16	Start camera check (is the start camera when not 0).
0x38	UInt16	Unknown.
0x3A	UInt16	Unknown.
0x3C	Int16	Linked Route ID (-1 if none).
0x3E	UInt16	Route Speed?
0x40	UInt16	End Zoom.
0x42	Int16	Next Camera (-1 if none).
0x44	String	Camera Name? (Most of the time "null" or "para").

Section 9

Section 9 describes Jugem points; the respawn positions. Each entry is a 0x20 byte structure as follows:

Offset	Type	Description
0x00	Float[3]	A 3D position vector of the respawn position.
0x0C	Int32[3]	A 3D rotation vector of the respawn position.
0x18	UInt16	Respawn ID?
0x1A	UInt16	Unknown.
0x1C	Int16	Unknown.
0x1E	Int16	Unknown.

Section 10

Unknown, but referenced as LightParam.

Offset	Type	Description
0x00	Int16	Unknown.
0x02	Int16	Unknown.
0x04	Float[3]	Unknown.
0x10	Int16	Unknown.
0x12	Int16	Unknown.

Section 11

This section is referenced as "MG" which can possibly stand for MiniGame. The section is always 0x40 bytes long, with each entry being 0x08 bytes long. After further reverse engineering, it has been found that this section is unused in the game. There's a game mode that is referenced as Rabbit, that has a check named isRidingBossPakkun, which means that this may have been Renegade Roundup, which appears in Mario Kart 8 Deluxe.

Offset	Type	Description
0x00	Int16	Unknown.
0x02	Int16	Unknown.
0x04	Int16	Unknown.
0x06	Int16	Padding.

Rotation Vector

The Mario Kart: Double Dash!! rotation vector consists of 3 Int32 values. The first two values form a two-dimensional direction vector with the first pointing in X-direction and the second pointing in Z-direction. The third value represents the length of the vector (it is quite inaccurate, though). Its value is usually 0x27100000 (655360000 in base 10). Using trigonometry, the rotation angle around the Y-axis can be calculated as follows:

angle (in degree) = sign(value1 + 0.5) * arccos(value2 / value3) * (180 / pi)

This C# snippet can properly determine the value as well:

public static double returnRotations(int xrot, int yrot, int zrot)
{
  double radToDeg = 57.2957795d;
  double angle1 = radToDeg * Math.Atan2((double)yrot / (double)zrot, (double)xrot / (double)zrot);
  angle1 = 90 - angle1;
  return angle1;
}

Tools

The following tools can handle BOL files:

• BOL Editor, by NiAlBlack
• Mario Kart DS Course Modifier, by Gericom (converts a BOL file to a NKM file)
• Wexos's Toolbox, by Wexos (only view)