Wave Traits
The wave traits page allows you to edit the traits for NPCs. Note that these traits are far less varied than player traits, and mainly concern AI behavior.
The fields available to edit are as follows:
- Damage Modifier
- Scales the amount of damage that NPC weapons and melees do.
- Damage Resistance
- Scales the amount of damage that NPCs can withstand. Note that this also scales the strength of breakable enemy armor, such as Grunt Ultras' helmets.
- Vision
-
Controls how likely an NPC is to notice an enemy within its line of sight.
The "Nearsighted" option reduces an NPC's sight range to 20% and reduces their field of view (i.e. vision cone angle) to 80%. The "Eagle Eye" option boosts their sight range to 150% and their field of view to 120%.
- Hearing
- Controls how likely an NPC is to notice enemies that are making noise. The "Sharp" option doubles the NPC's hearing range.
- Luck
-
Controls how likely an NPC is to dodge grenades and needles, versus how likely an NPC Grunt is to flee or attempt a suicide bombing.
- Unlucky
- Never evades fire, dives away from grenades, or attempts a suicide bombing. Always retreats after diving. Never goes berserk after shields pop. Leaders don't go berserk after their followers are all killed.
- Normal
- No changes are made to the base AI data.
- Lucky
- 75% more likely to evade fire and dive away from grenades. Never retreats after diving. The delays between successive melee attacks, and successive grenade throws, are halved. Twice as likely to melee.
- Leprechaun
- Evades fire and dives away from grenades as often as is physically possible. Never retreats after diving. Always attempts a suicide bombing when "broken." Always retreats when their leader dies. Always goes berserk when their shields pop. Leaders always go berserk when their followers are all killed. The delays between successive melee attacks, and successive grenade throws, are halved. Always melees when it is possible to do so.
- Shootiness
-
Controls NPCs' accuracy and tendency to fire excess shots.
- Grenades
- Controls how often NPCs use grenades. The "Catch" option significantly increases the NPC's likelihood of throwing grenades, halves the delay between successive grenade throws, and doubles grenades' outbound velocity.
- Don't Drop Equipment on Death
- If this option is enabled, then NPCs will not drop weapons or grenades when they die.
- Assassination Immunity
- Controls whether NPCs are immune to instant-kill melees to the back, and to special finishing moves (which players will not be allowed to perform).
- Headshot Immunity
- Controls whether NPCs are immune to instant-kill headshots.
All exact stats for AI changes are based on examination of the game data using the Halo: Reach Editing Kit. Not all behaviors (e.g. "going berserk") may apply to all NPC types.
Under the hood
The effects of the Vision, Hearing, Luck, and Grenades options are all defined in
the globals\ai_globals.ai_globals
tag.
The effects of the Shootiness option appear to be defined on character
tags. The tags/ai/generic.character
tag defines defaults that can be
overridden by each individual NPC type. Within a character tag, "firing patterns"
(with the same names as the Shootiness option values) can be defined per weapon, and
the parameters associated with a firing pattern include:
- How many times per second they pull the trigger
- How long each burst they fire is
- How long they wait between bursts
- The distance by which they are likely to miss their target when they begin firing a burst (such that they have to correct their aim over time)
- The maximum angle by which they can miss their target when they begin firing a burst
- How well they can track a moving target, in terms of how well they adjust their aim after they begin firing a burst
- How well they can lead a moving target, predicting its movement