Subobject and subsystem properties

This page documents the properties that can be applied to subobjects and to subsystems in their respective properties data in the model file.

Important notes

• Subobject/subsystem properties data can be parsed in any order.
• Occasionally an option may lack a trailing 'terminating character' like ':' or '=' from its description. In these cases any character can be used as the trailing 'terminating character'.
• Buffer size of 256 is reserved for the characters in properties data.

Subsystem Properties

• These can be applied to subsystems, some of which require the subsystem to have an associated subobject.

Key strings and their order for setting subsystems
engine	Engine subsystem
radar	Radar dish subsystem
turret	Turret subsystem
navigation	Navigation subsystem
communication	Communication subsystem
weapon	Weapon control subsystem
sensor	Sensor subsystem
solar	Solar panel subsystem
gas	Gas collector subsystem
activator	unused

$name

• Defines the alternate name for the subsystem (string)
• Alternate subsystem names offer an alternative option for setting this via ships.tbl file or via mission data.

$fov

• Valid only if the true subobject name (not the alternate defined above) contains string "turret" but not strings "radar" or "engine"
• Defines the firing arc of the turret in degrees (integer)
• Defaults to 180 degrees if omitted.

$crewspot

• Valid only if the true subobject name (not the alternate defined above) contains string "turret" but not strings "radar" or "engine"
• Marks the turret as 'crewspot'
• Defines the name of the crewspot (string)
• No actual function

$triggered:

• Defines the subsystem as a rotating subsystem which can be triggered (animated) via Animation Code

$rotate

• Marks the subsystem as a rotating subsystem
• Defines the rotation time for the subsystem: the number of seconds to make a complete rotation (float)

$rotate_time

• Marks the subsystem as a rotating subsystem - alternative to $rotate
• Defines the rotation time for the subsystem: the number of seconds to make a complete rotation (float)

$rotate_rate

• Marks the subsystem as a rotating subsystem - alternative to $rotate, with different units
• Defines the rotation rate for the subsystem: the rotational velocity in radians per second (float)

FS2 Open, 22.0:

$rotate_accel

• Specifies the acceleration for a rotating or dumb-rotating subobject. If not specified, acceleration is 0.5 radians per second per second (float, or "instant")

$pbank

• Marks the rotation as primary weapon rotation
• Defines the associated weapon bank (integer)

$stepped

• Defines the rotation as a stepped instead of continuous rotation

$steps

• Defines the number of steps per complete rotation (integer)
• Defaults to 8

$t_paused

• Defines the pause time, in seconds, between steps (float)
• Defaults to 2

$t_transit

• Defines the movement time, in seconds, between pauses (float)
• Defaults to 2

$fraction_accel

• Defines the fraction of the stepped rotation time used for acceleration (float)
• Must be between 0 .. 0.5
• Defaults to 0.3

FS2 Open, 23.0:

$translate

• Marks the subsystem as a translating subsystem
• Defines the translation rate for the subsystem: the linear velocity in meters per second (float)

$translate_rate

• Marks the subsystem as a translating subsystem - alternative to $translate
• Defines the translation rate for the subsystem: the linear velocity in meters per second (float)

$translate_accel

• Specifies the acceleration for a translating subobject. If not specified, acceleration is 0.5 meters per second per second (float, or "instant")

$stepped

• Defines the translation as a stepped instead of continuous translation

$reverse_after_step

• Defines whether the subsystem should reverse direction after every step (boolean)
• Defaults to true

$step_distance

• Defines the distance, in meters, covered by one complete step (float)
• Defaults to 25

$t_paused

• Defines the pause time, in seconds, between steps (float)
• Defaults to 2

$t_transit

• Defines the movement time, in seconds, between pauses (float)
• Defaults to 2

$fraction_accel

• Defines the fraction of the stepped translation time used for acceleration (float)
• Must be between 0 .. 0.5
• Defaults to 0.3

Subobject Properties

• These can be applied only to subsystem with their own separate subobject, or subobjects without subsystems.

$dumb_rotate:

• Marks the subobject as a 'dumb rotating submodel' (i.e. a submodel that rotates but doesn't require a corresponding subsystem)
• Defines the rotation time for the subobject: the number of seconds to make a complete rotation (float)

$dumb_rotate_time

• Marks the subobject as a 'dumb rotating submodel' - alternative to $dumb_rotate
• Defines the rotation time for the subobject: the number of seconds to make a complete rotation (float)

$dumb_rotate_rate

• Marks the subobject as a 'dumb rotating submodel' - alternative to $dumb_rotate, with different units
• Defines the rotation rate for the subobject: the rotational velocity in radians per second (float)

$look_at:

• Causes the subobject to always "look at" (i.e. point to by rotating on its axis) the origin of another subobject
• Integer index or string name of the subobject target

$look_at_offset:

• Defines an angle offset for a $look_at: submodel
• Float angle in degrees
• Note: if $look_at_offset is not specified, it will be set to the submodel's initial position. In other words, the initial position is considered to be the default forward direction.

FS2 Open, 25.0:

In 25.0, if the submodel's $fvec/$uvec is specified but $look_at_offset is not, $look_at_offset is set to 0 instead of the submodel's initial position. In other words, the $fvec/$uvec is considered to determine the forward direction.

$special

• Defines special attributes for the subobject
• String, either "subsystem", "no_rotate" or "shieldpoint"

"subsystem"

• subsystem marks the subobject as an subsystem

"no_rotate"

• Valid option if subsystem string was not used
• Marks subobject as an object that should not rotate

"shieldpoint"

FS2 Open, 3.7.2:

• Only usable on special points (not on submodels).
• Marks the special point as a shield point, see Model Point Shields.

$no_collisions

• Prevents collision detection from occurring on this subobject and all of its children (recursively).

$nocollide_this_only

• Prevents collision detection from occurring on this subobject only (children collide normally).

$collide_invisible

• Allows full collision detection for things painted with the special "invisible" texture (normally ships collide but weapons do not)

$gun_rotation:

• Marks the submodel as using gun rotation

$detail_box:

• Marks the subsystem as one with detail box

$box_offset:

FS2 Open, 3.7.4:

• Optional offset of the detail box from the model center. Without this, the detail box is centered on the submodel.
• Example: $offset: 0,0,-100.5 to make the detail box be positioned 100.5m behind the ship's center.

$detail_sphere:

FS2 Open, 3.6.16:

• Marks the subsystem as one with detail sphere. Detail spheres work exactly like detail boxes (see above), except that they only define a radius instead of a box.

$radius:

FS2 Open, 3.6.16:

• Defines the radius of the detail sphere (float). If not provided, defaults to the submodel radius.

$offset:

FS2 Open, 3.6.16:

• Optional offset of the detail sphere from the model center. Without this, the detail sphere is centered on the submodel.
• Example: $offset: 0,0,-100.5 to make the detail sphere be positioned 100.5m behind the ship's center.

$rotation_axis:

FS2 Open, 21.0:

• Defines the custom rotation axis of a submodel. The point represents an axis vector in a particular direction, just like the X axis is the {1,0,0} vector.
• Reads three comma separated floats enclosed in square or curly brackets. It does not need to be a normalized vector.
• $rotation_axis can be followed by whitespace, a colon, or an equals sign.

$translation_axis:

FS2 Open, 23.0:

• Defines the custom translation axis of a submodel. The point represents an axis vector in a particular direction, just like the X axis is the {1,0,0} vector.
• Reads three comma separated floats enclosed in square or curly brackets. It does not need to be a normalized vector.
• $translation_axis can be followed by whitespace, a colon, or an equals sign.

$fvec:

FS2 Open 3.6.10:

• Defines the forward vector of the orientation matrix for a rotating subsystem. This can be used to create off-axis rotating subsystems or off-axis multipart turrets. (Multiparts with a vertical rotation axis do not need $fvec/$uvec/$rvec specified.)
• Reads three comma separated floats. It does not need to be a normalized vector.
• As of 20.2, $fvec can be followed by whitespace, a colon, or an equals sign.
• As of 25.0, $fvec can be specified on its own (without $uvec or $rvec), although for certain orientations $uvec or $rvec is still necessary.

$uvec:

FS2 Open 3.6.10:

• Defines the up vector of the orientation matrix for a rotating subsystem. This can be used to create off-axis rotating subsystems or off-axis multipart turrets. (Multiparts with a vertical rotation axis do not need $fvec/$uvec/$rvec specified.) Usually it stands perpendicular to the ship surface.
• Reads three comma separated floats. It does not need to be a normalized vector.
• Forces turret normal into the same as the $uvec.
• As of 20.2, $uvec can be followed by whitespace, a colon, or an equals sign.
• As of 25.0, $rvec can be specified in addition, or as an alternative.

$rvec:

FS2 Open, 25.0:

• Defines the right vector of the orientation matrix for a rotating subsystem. This can be used to create off-axis rotating subsystems or off-axis multipart turrets. (Multiparts with a vertical rotation axis do not need $fvec/$uvec/$rvec specified.)
• Reads three comma separated floats. It does not need to be a normalized vector.
• Can be specified in addition, or as an alternative, to $uvec.

$lod0_name

• Allows adding LODs to older models and changing from special points to modeled subsystems.
• Example $lod0_name=enginea used on a subobject named engine would allow engineb, engienc, and engined to be used while preserving backward compatibility.

$attach_thrusters

FS2 Open, 3.6.16:

• Allows thrusters associated with this submodel to follow its rotations.

Warning: This flag is redundant. This behavior is active regardless of this flag.