SEC files contain the navigation mesh of a map. It is used for pathfinding an for calculating the field of view (view cone).

Bel sec navmesh

Navigation Mesh in Commandos BEL

File structureEdit

example description
841 number of vertices
1354.74 3554.83 vertex 0
1331 3592.17 vertex 1
1297 3573.5 vertex 2
1295 3503.71 vertex 3
... (more vertices)
552 number of sectors
4 0 0 0 2 0 0 384 #Vertices, kx, ky, bz, Type, Height, Offset, Flags
0 vertex index
1 vertex index
2 vertex index
3 vertex index
... (more sectors)
1 number of bridge sectors
4 0 0 0 0 0 0 386 (same structure as regular sectors)
1 number of areas
61 CAMP number of sectors, area name
0 17 sector type, sector index
0 18 (sector type 0 = regular sector, 1 = bridge sector)
0 22
... (more sectors)
1 number of connected sectors (used for climbable areas)
8 20 first sector, second sector
... (more connections)


XY coordinates on the map, e.g: 415.685 625.946

Hint for programmers:
In Commandos the player looks down at the map from an angle of 40 degrees. That means that the y-coordinates have to multiplied by sin(40) to get the correct screen coordinates.


A Sector is a convex polygon defined by multiple vertices.

kx, ky, bzEdit

kx = the tangent of the angle to the X-axis   
ky = the tangent of the angle to the Y-axis
bz = the intercept for Z-axis

equation for the plane of a sector:
z = kx * x + ky *y + bz


Defines the terrain type of a sector

Type Description
0 land (default)
1 shallow water
2 snow or sand (characters leave footprints)
3 deep water
4 conveyor (used in mission 19)

Height and OffsetEdit

Height = height of the sector

Offset = final height of a stair or a ramp.


Flag Description
1 sector is stair (or ramp)
2 sector is bridge
4 not enterable by all units (used for fences)
8 not enterable by enemies
16 blocks sight (used for walls, rocks and buildings)

(never used)

64 climbable wall

Normal sectors have the flag 384.

Blocked sectors have the flag 276.

Sectors that cannot be walked on (but can be looked through) have either the flag 260 (view cone is not visible) or flag 4 (view cone is visible on this sector).

Bridge SectorsEdit

These special sectors lead over the normal sectors, you can walk on and under them. They have the
same structure like ordinary sectors, except for the additional flag set (see Flags).


Areas are used for the enemy AI. When the same soldier reacts in another way after he spotted you (for example inside or outside a base), this happens due to the different areas. How the enemy reacts is actually defined in the mission file MIS.

Sector Type

0 = regular sector
1 = bridge sector

Connected SectorsEdit

This information is used to tell the Green Beret which walls he can climb, e.g. the huge wall to the east in the mission 'Blind Justice' has been declared this way. Nearly all walls already are defined in the sector information with the flag 448.

Differences between BEL and BCDEdit

SEC files in BCD have a different file format but they contain nearly the same information. BCD can read both formats, BEL can't read the BCD format.

Additional information in the SEC files from BCD:

  1. Vertices kx ky bz Type Height Offset Flags TokenLength Token

Most sectors don't have a Token so the TokenLength is 0. If the TokenLength is not zero, there will be
an entry in MIS file with the Token.

For more information see: BCD File Format