unit (abstract tag)

Vehicles and bipeds are both extensions of the Unit abstract tag class, which is not directly creatable itself. Generally, units are controllable objects which can "die" and appear on the motion sensor.

Feigning death

...

Structure and fields

Field Type Comments

unit flags bitfield

Flag	Mask	Comments
circular aiming	`0x1`
destroyed after dying	`0x2`
half speed interpolation	`0x4`
fires from camera	`0x8`
entrance inside bounding sphere	`0x10`
unused	`0x20`
causes passenger dialogue	`0x40`
resists pings	`0x80`
melee attack is fatal	`0x100`
don't reface during pings	`0x200`
has no aiming	`0x400`
simple creature	`0x800`
impact melee attaches to unit	`0x1000`
impact melee dies on shields	`0x2000`
cannot open doors automatically	`0x4000`
melee attackers cannot attach	`0x8000`
not instantly killed by melee	`0x10000`	If enabled, prevents the unit from being instantly killed by a melee to their back. This is used for the Flood.
shield sapping	`0x20000`
runs around flaming	`0x40000`
inconsequential	`0x80000`
special cinematic unit	`0x100000`
ignored by autoaiming	`0x200000`
shields fry infection forms	`0x400000`
integrated light cntrls weapon	`0x800000`
integrated light lasts forever	`0x1000000`

default team enum

Option	Value	Comments
none	`0x0`
player	`0x1`
human	`0x2`
covenant	`0x3`
flood	`0x4`
sentinel	`0x5`
unused6	`0x6`
unused7	`0x7`
unused8	`0x8`
unused9	`0x9`

constant sound volume enum

Option	Value	Comments
silent	`0x0`
medium	`0x1`
loud	`0x2`
shout	`0x3`
quiet	`0x4`

rider damage fraction

float

Min: 0

integrated light toggle TagDependency: effect

unit a in enum

Option	Value	Comments
none	`0x0`
driver seat power	`0x1`
gunner seat power	`0x2`
aiming change	`0x3`
mouth aperture	`0x4`
integrated light power	`0x5`
can blink	`0x6`
shield sapping	`0x7`

unit b in enum^?

unit c in enum^?

unit d in enum^?

camera field of view

float

Default: 1.22173

camera stiffness float

camera marker name TagString

camera submerged marker name TagString

pitch auto level float

pitch range Bounds

Field	Type	Comments
min	`float`
max	`float`

camera tracks Block

Field	Type	Comments
track	`TagDependency`: camera_track

seat acceleration scale Point3D

Field	Type	Comments
x	`float`
y	`float`
z	`float`

soft ping threshold

float

Min: 0
Max: 1

soft ping interrupt time

float

Unit: seconds

hard ping threshold

float

Min: 0
Max: 1

hard ping interrupt time

float

Unit: seconds

hard death threshold

float

Min: 0
Max: 1

feign death threshold

float

Min: 0
Max: 1

feign death time

float

Unit: seconds

distance of evade anim

float

Unit: world units

distance of dive anim

float

Unit: world units

stunned movement threshold

float

Min: 0
Max: 1

feign death chance

float

Min: 0
Max: 1

feign repeat chance

float

Min: 0
Max: 1

spawned actor TagDependency: actor_variant

spawned actor count Bounds

Field	Type	Comments
min	`uint16`
max	`uint16`

spawned velocity float

aiming velocity maximum

float

Unit: degrees per second

aiming acceleration maximum

float

Unit: degrees per second squared

casual aiming modifier

float

Min: 0
Max: 1

looking velocity maximum

float

Unit: degrees per second

looking acceleration maximum

float

Unit: degrees per second squared

ai vehicle radius float

ai danger radius float

melee damage TagDependency: damage_effect

motion sensor blip size enum

Option	Value	Comments
medium	`0x0`
small	`0x1`
large	`0x2`

metagame type

enum

H1A only

Only used for scoring in H1A (MCC only); overridden by actor_variant's metagame type if unit is an actor.

Option	Value	Comments
brute	`0x0`
grunt	`0x1`
jackal	`0x2`
skirmisher	`0x3`
marine	`0x4`
spartan	`0x5`
bugger	`0x6`	Also called "drone".
hunter	`0x7`
flood infection	`0x8`
flood carrier	`0x9`
flood combat	`0xA`
flood pure	`0xB`
sentinel	`0xC`
elite	`0xD`
engineer	`0xE`	Also called "huragok".
mule	`0xF`
turret	`0x10`
mongoose	`0x11`
warthog	`0x12`
scorpion	`0x13`
hornet	`0x14`
pelican	`0x15`
revenant	`0x16`
seraph	`0x17`
shade	`0x18`
watchtower	`0x19`
ghost	`0x1A`
chopper	`0x1B`
mauler	`0x1C`	Also called "prowler".
wraith	`0x1D`
banshee	`0x1E`
phantom	`0x1F`
scarab	`0x20`
guntower	`0x21`
tuning fork	`0x22`	Also called "spirit".
broadsword	`0x23`
mammoth	`0x24`
lich	`0x25`
mantis	`0x26`
wasp	`0x27`
phaeton	`0x28`
bishop	`0x29`	Also called "watcher".
knight	`0x2A`
pawn	`0x2B`	Also called "crawler".

metagame class

enum

H1A only

Only used for scoring in H1A (MCC only); overridden by actor_variant's metagame class if unit is an actor.

Option	Value	Comments
infantry	`0x0`
leader	`0x1`
hero	`0x2`
specialist	`0x3`
light vehicle	`0x4`
heavy vehicle	`0x5`
giant vehicle	`0x6`
standard vehicle	`0x7`

new hud interfaces

Block

HEK max count: 2

Field	Type	Comments
hud	`TagDependency`: unit_hud_interface

dialogue variants

Block

HEK max count: 16

Field	Type	Comments
variant number	`int16`
dialogue	`TagDependency`: dialogue

grenade velocity

float

Unit: world units per second

The velocity of thrown grenades. This field is used for the player, but overidden by actor_variant grenade velocity for AI. The projectile initial velocity for grenades is not used.

grenade type enum

Option	Value	Comments
human fragmentation	`0x0`
covenant plasma	`0x1`

grenade count uint16

soft ping interrupt ticks

int16

Cache only

hard ping interrupt ticks

int16

Cache only

powered seats

Block

HEK max count: 2

Field	Type	Comments
driver powerup time	`float`	Unit: seconds
driver powerdown time	`float`	Unit: seconds

weapons

Block

HEK max count: 4

Field	Type	Comments
weapon	`TagDependency`: weapon

seats

Block

HEK max count: 16

Field Type Comments

flags bitfield

Flag	Mask	Comments
invisible	`0x1`
locked	`0x2`
driver	`0x4`
gunner	`0x8`
third person camera	`0x10`
allows weapons	`0x20`
third person on enter	`0x40`
first person camera slaved to gun	`0x80`
allow vehicle communication animations	`0x100`
not valid without driver	`0x200`
allow ai noncombatants	`0x400`

label TagString

marker name TagString

acceleration scale Vector3D

Field	Type	Comments
i	`float`
j	`float`
k	`float`

yaw rate

float

Unit: degrees per second

pitch rate

float

Unit: degrees per second

camera marker name TagString

camera submerged marker name TagString

pitch auto level float

pitch range Bounds^?

camera tracks

Block^?

HEK max count: 2

unit hud interface

Block^?

HEK max count: 2

hud text message index uint16

yaw minimum float

yaw maximum float

built in gunner

TagDependency: actor_variant

Used to place a mounted weapon unit at this seat, which aims and fires independently of this unit. An example is the bottom-mounted turret on the covenant dropship. The game can only simulate up to 8 of these mounted units at a time.

Acknowledgements

Thanks to the following individuals for their research or contributions to this topic:

Kavawuvi (Invader tag definitions)
MosesOfEgypt (Tag structure research)