Customizing Mob AI

MythicMobs provides the ability to program custom mob AI in your mobs which allows for a huge amount of additional customization as to how mobs attack, what targets they choose to attack, and other actions.

In the following sections I will provide some examples on how to configure a couple common scenarios that you may want to use on your server.

AI Goals, Targets, and Factions

  • Custom AI generally requires two things configured in order to work. You need AI Goals, which tell the mob how it should act, and you need AI Targets which tells the mob how it should target things.
  • Factions are used to separate mobs into groups and will be used later for more advanced configurations.
  • By default, all minecraft mobs have some sort of internal AI that tells them how their AI should work. As an example, the Skeleton AI says that it should target players and that it should use the arrow attack option when attacking said players. In order to re-program the skeleton AI using MythicMobs we must first clear its AI goals and targets and then add new objectives to these areas.
  • Lets take a look at an example below.

DecayingSkeleton:
  Mobtype: skeleton
  Display: '&aa decaying skeleton'
  Health: 15
  Damage: 1
  Faction: Undead
  AIGoalSelectors:
  - 0 clear
  - 1 arrowattack
  AITargetSelectors:
  - 0 clear
  - 1 players
  Options:
    FollowRange: 10
    MovementSpeed: 0.2
    PreventOtherDrops: true

  • This example shows how the Skeleton AI generally works for attacking. (minus all the fluff, such as randomly walking around).
    • The AIGoalSelectors section tells the Skeleton Mob to use the arrowattack action when it is going about its day to day goals.
    • The AITargetSelectors section tells the Skeleton Mob that it should look to target players to use the arrowattack action on.
    • As you see clear is always first, which in this case wipes the mobs AI so you have a clean slate to work with. This is important otherwise your AI may not function the way you would expect.
  • Now lets say we want the skeleton to attack other mobs instead and we want him to use a melee attack instead of a ranged attack. See below for how we accomplish this.

DecayingSkeleton:
  Mobtype: skeleton
  Display: '&aa decaying skeleton'
  Health: 15
  Damage: 1
  Faction: Undead
  AIGoalSelectors:
  - 0 clear
  - 1 meleeattack
  AITargetSelectors:
  - 0 clear
  - 1 hurtbytarget
  - 2 otherfactionmonsters
  Equipment:
  - COS_WoodSword:0
  Options:
    FollowRange: 10
    MovementSpeed: 0.2
    PreventOtherDrops: true

  • The skeleton AI now is programmed to attack other mobs, and any mobs that attack it first. In addition, it will use the melee attack instead of ranged attack.
    • The AIGoalSelectors section now has the meleeattack goal which says to attack using melee. It should be noted that you must equip the skeleton with a sword now so he can use the melee attack since you can't melee with a bow equipped (the skeletons default weapon) This would not be required however for a zombie.
    • The AITargetSelectors section now has the players target removed so the skeleton will not actively engage players. Instead it has the otherfactionmonsters target, which tells it that it should attack any monsters that are not in its own faction (in this case Undead). There is also hurtbytarget selector with a priority of 1 which says that if any other entities attacks the skeleton first (such as a player) then it will retaliate. This target selector is a common one that should be set as a higher priority so that mobs don't end up being exploitable. Without this here, the player could kill the skeleton without it attacking back which generally is not wanted.
  • For a list of all the target and goal selectors please see Mob AI Goals
  • In the next two sections I will provide some examples for AI configuration for two common scenarios you may wish to implement on your server.

Example 1: Guards attack nearby monsters

  • In this scenario we want to setup some guards at the entrance to our city which should repel monsters that wander too close. You could use an Iron Golem for this function disguised as a villager, but their AI harder to control and they have special knock-up attacks that make it unfair for the mobs, so we're going to use MythicMobs' Custom AI to accomplish the same thing in a better way.
  • The first thing we need is a beefy guard mob to protect our town. Lets create a skeleton disguised as a villager, and equip him with a sword.

SummonedGuard1:
  Mobtype: skeleton
  Display: '&Ea town guard'
  Health: 500
  Damage: 5
  Equipment:
  - COS_StoneSword:0
  Options:
    Disguise: villager
    Despawn: true
    FollowRange: 5
    AlwaysShowName: false
    MovementSpeed: 0.35
    PreventOtherDrops: true
    KnockbackResistance: 1
    PreventMobKillDrops: true

  • So if we tie this mob to a mob spawner at our gates, he's going to go attack all of our players in the town so we need to make some adjustments to make him friendly.

SummonedGuard1:
  Mobtype: skeleton
  Display: '&Ea town guard'
  Health: 500
  Damage: 5
  Equipment:
  - COS_StoneSword:0
  Faction: Guard
  AIGoalSelectors:
  - 0 clear
  - 1 opendoors
  - 2 meleeattack
  AITargetSelectors:
  - 0 clear
  - 1 hurtbytarget
  - 2 otherfactionmonsters
  Options:
    Disguise: villager
    Despawn: true
    FollowRange: 5
    AlwaysShowName: false
    MovementSpeed: 0.35
    PreventOtherDrops: true
    KnockbackResistance: 1
    PreventMobKillDrops: true

  • Now the mob will target other factions containing monsters besides his own and will target anyone that hurts him (this will keep some of our less ethical players from killing our guards for the hell of it) He will also open any doors in his way to get to his target.
  • So this is the first half of the problem. Next we need to ensure that our monsters that are roaming outside our walls will attack back against our guards.
  • Below we will grab our Decaying Skeleton mob and configure him as such.

DecayingSkeleton:
  Mobtype: skeleton
  Display: '&aa decaying skeleton'
  Health: 15
  Damage: 1
  Faction: Undead
  AIGoalSelectors:
  - 0 clear
  - 1 meleeattack
  AITargetSelectors:
  - 0 clear
  - 1 hurtbytarget
  - 2 players
  Equipment:
  - COS_RawHead:4
  - COS_WoodSword:0
  Options:
    Despawn: true
    FollowRange: 10
    AlwaysShowName: false
    MovementSpeed: 0.2
    PreventOtherDrops: true

  • Our decaying skeleton is now in the Undead faction (different then the Guard faction) and so he will be attacked by the guard. Also, by adding the hurtbytarget target selector, our decaying skeleton will now fight back if engaged with a guard (and ultimately die)
  • For any other mobs we have that spawn near the town, we would want to add the the same AI Goals and Targets as configured above for the skeleton making sure that the mob has a different faction then the guard.
  • Now when we setup our mob spawners for our town guard at the gates, he will repel monsters but ignore players (as long as they leave the guard alone)
  • Some additional settings that we would probably want to set in this case are a short follow range for the guard (5 in this case) and a short leash range for the mob spawner. This will ensure that the guard doesn't go off on a rampage and kill all the monsters that we want our players to be able to kill for experience and loots. We also want to ensure that the guard has the PreventMobKillDrops set to true so that his kills don't drop exp/loot for our players.

Example 2: Orcs and Goblins attack each other

  • So in our world we have two factions, the goblins and the orcs and they don't like each other much. We have a battlefield setup where they are at constant war except right now they are both using the skeleton mob type with its default AI and they aren't doing much fighting.
  • We want to configure them using Mythic Mobs Custom AI so that they fight each other when nearby in addition to any players that wander onto the battlefield.
  • Lets create an Orc mob and a Goblin mob.

OrcCenturion:
  Mobtype: villagezombie
  Display: '&aan orc centurion'
  Health: 50
  Damage: 4
  Faction: Orcs
  AIGoalSelectors:
  - 0 clear
  - 1 opendoors
  - 2 meleeattack
  AITargetSelectors:
  - 0 clear
  - 1 hurtbytarget
  - 2 specificfactionmonsters Goblin
  - 3 players
  Equipment:
  - C_DeathfistSkullcap:4
  - C_DeathfistTunic:3
  - C_DeathfistLeggings:2
  - C_DeathfistBoots:1
  - COS_WoodSword:0
  Options:
    Despawn: true
    FollowRange: 10
    AlwaysShowName: false
    MovementSpeed: 0.25
    PreventOtherDrops: true
    PreventItemPickup: true
    KnockbackResistance: 0.25
    PreventMobKillDrops: true
    
GoblinBattlemaster:
  Mobtype: zombie
  Display: '&aa goblin battlemaster'
  Health: 80
  Damage: 4
  Faction: Goblin
  AIGoalSelectors:
  - 0 clear
  - 1 opendoors
  - 2 meleeattack
  AITargetSelectors:
  - 0 clear
  - 1 hurtbytarget
  - 2 specificfactionmonsters Orcs
  - 3 players
  Equipment:
  - COS_BronzeHead:4
  - COS_BronzeChest:3
  - COS_BronzeLegs:2
  - COS_BronzeFeet:1
  - COS_WoodAxe:0
  Skills:
  - skill BashI ~onAttack >0 0.25
  Options:
    Despawn: true
    FollowRange: 10
    AlwaysShowName: false
    MovementSpeed: 0.25
    PreventOtherDrops: true
    PreventItemPickup: true
    KnockbackResistance: 0.4    
    PreventMobKillDrops: true

  • So there are a few things we've configured here of note.
    • First we have set the orc mob on the Orc Faction and the Goblin mob on the Goblin Faction. This will logically separate the two mob types.
    • Next we configure both of the mobs with the standard clear, opendoors, and meleeattack actions which is common for most melee type mobs.
    • Lastly we clear our AI then setup three AI target selectors.
  • First is the hurtbytarget selector which as mentioned before is a good fall back option so that mobs can not be exploited by other mobs or players that they will not retaliate against.
  • Next is the specifictargetfaction selector with the opposing faction in it. This is set to priority 2 so the goblins and orcs will target each other first when they aren't already in combat
  • Last is the players target selector which tells that mobs to attack players if there are no goblins/orcs nearby.
  • Lastly remember to set the PreventMobKillDrops to true so that warring npc factions don't drop exp / loots for players that happen to wander by.
  • If we have other goblin or orc mob types, we need only copy and paste these AI configurations into their mob setups and they should react similarly to the two mobs above.
tutorials/customai.txt · Last modified: 2016/03/04 07:07 (external edit)
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