MonsterAIRule

Time-based and event-triggered AI Unit overrides for monsters

Defines conditional rules that can temporarily override a monster's AI Unit based on time, date, or server events. This allows monsters to change their entire behavior pattern during specific periods.

File Location

GameServer/Data/Monster/MonsterAIRule.xml

Dependencies

Depends On	Purpose
MonsterAIUnit.xml	Rules override monsters with different AI Units
MonsterAIGroup.xml	Defines monsters' default AI Units

Used By	Purpose
Monster AI System	Evaluated every AI tick to check for active rules

How It Works

MonsterAIRule allows you to temporarily replace a monster's AI Unit based on conditions:

1. Normal behavior: Monster uses its BasicAI (from MonsterAIGroup.xml)

2. Rule activates: When a rule's condition is met, the monster switches to the rule's Unit

3. Behavior changes: The monster now uses a completely different AI personality

4. Rule expires: After WaitTime + ContinuanceTime, monster reverts to BasicAI

This is an AI Unit override system, not a stat modifier. Rules completely replace the monster's behavior pattern (Automata, Elements, timing) for the duration of the rule.

Rule Evaluation

Rules are evaluated every AI tick (MonsterAIProc) for every active monster:

1. Check if rule condition is valid (date/time/event match)

2. Check if WaitTime has elapsed since condition became valid

3. Check if we're still within WaitTime + ContinuanceTime

4. If all checks pass, override the monster's CurrentAI with the rule's Unit

Current Status

The default configuration file is empty (no active rules). The system is fully functional and loaded at server startup, but requires you to define rules to use it.

<?xml version="1.0" ?>
<MonsterAIRule/>

Configuration Structure

Rule Attributes

Attribute	Type	Required	Description
Number	int	Yes	Unique rule identifier
Class	int	Yes	Monster class ID to apply rule to (all monsters of this class)
Description	string	No	Human-readable rule description
Unit	int	Yes	AI Unit to override with (from MonsterAIUnit.xml)
Condition	int	Yes	Condition type: 1 = Date/Time, 71 = Crywolf Start, 72 = Crywolf End
WaitTime	int	Yes	Seconds to wait after condition becomes true before activating
ContinuanceTime	int	Yes	Seconds the rule stays active after WaitTime expires
Month	int/string	Conditional	Month (1-12) or * for any month
Day	int/string	Conditional	Day (1-31) or * for any day
WeekDay	int/string	Conditional	Weekday (0=Sunday, 6=Saturday) or * for any day
Hour	int/string	Conditional	Hour (0-23) or * for any hour
Minute	int/string	Conditional	Minute (0-59) or * for any minute

Wildcard *: Use * to ignore a date/time field. For example, Hour="*" matches all hours.

Condition Types

Condition	Description	Date/Time Fields Used
1	Specific Date/Time	All date/time attributes apply
71	Crywolf Event Start	Not implemented (always returns false)
72	Crywolf Event End	Not implemented (always returns false)

Crywolf conditions (71, 72) are not implemented in the current version. Use Condition 1 (Date/Time) for functional rules.

Important Behavior

Timing Logic

The rule activation follows this timeline:

Condition becomes TRUE → Wait [WaitTime] seconds → Rule ACTIVE for [ContinuanceTime] seconds → Rule EXPIRES

Example: Halloween rule with WaitTime="10" and ContinuanceTime="3600"

• October 31, 00:00:00 → Condition becomes true

• October 31, 00:00:10 → Rule activates (10 second wait)

• October 31, 01:00:10 → Rule expires (3600 second duration)

Date/Time Matching

• All specified fields must match: If you set Month="10" and Hour="20", the rule only activates on October at 8 PM

• Wildcards ignore fields: Month="*" means the rule ignores the month completely

• ValidRange calculation: The WaitTime + ContinuanceTime defines how long the condition can remain true

• Minute-precision: Time matching is precise to the minute

Multiple Rules Per Monster

If multiple rules target the same monster class:

• The last valid rule in the array takes precedence

• Rules are evaluated in order from first to last

• Only one AI Unit override can be active at a time

Performance Impact

Rules are evaluated every AI tick for every active monster. Keep the number of rules reasonable (under 50) to avoid performance issues.

Examples

Halloween Night Bosses

Make Golden Goblins (class 8) super aggressive on Halloween night:

<MonsterAIRule>
  <!-- Halloween: Golden Goblins become aggressive hunters -->
  <Rule
    Number="1"
    Class="8"
    Description="Halloween aggressive Golden Goblin"
    Unit="101"
    Condition="1"
    WaitTime="0"
    ContinuanceTime="86400"
    Month="10"
    Day="31"
    WeekDay="*"
    Hour="*"
    Minute="*"
  />
</MonsterAIRule>

• Activates on October 31 at midnight

• Switches Golden Goblins to AI Unit 101 (aggressive hunter behavior)

• Lasts for 86400 seconds (24 hours)

• All Golden Goblins on the server are affected

Weekend Night Events

Rush Hour Aggression

Delayed Event Start

Common Issues

Rule Not Activating: Check that:

• The Unit exists in MonsterAIUnit.xml

• The Class matches monsters in MonsterAIGroup.xml

• Date/time fields are correct (0-based WeekDay: Sunday=0)

• Condition is 1 (not 71 or 72, which don't work)

Rules Expire Too Quickly: The ContinuanceTime is in seconds, not minutes. Common mistake: setting ContinuanceTime="60" for 60 minutes (actually only 1 minute). Use ContinuanceTime="3600" for 1 hour.

Wrong Time Zone: Server time is based on system clock. Ensure your server's system time and timezone are correct.

Use Cases

Time-Based Events

• Night aggression: Make monsters more aggressive at night (Unit with lower DelayTime, aggressive Automata)

• Weekend bosses: Spawn event bosses only on weekends

• Hourly rotations: Rotate monster behavior every few hours

Seasonal Events

• Halloween: Spooky behavior on October 31

• Christmas: Festive monster patterns in December

• Anniversary: Special AI during server anniversary dates

Dynamic Difficulty

• Peak hour challenge: Harder AI during peak player hours

• Off-peak relaxation: Easier AI during low-population times

• Weekly cycles: Escalating difficulty through the week

When NOT to Use MonsterAIRule

MonsterAIRule is powerful but not always the right tool:

Need	Better Solution
Permanent behavior changes	Modify MonsterAIGroup.xml directly
HP-based skill triggers	Use MonsterSkill.xml
Timed spawns/despawns	Use MonsterSetBase.xml Type 3 (event-based spawns)
Event-specific monsters	Create event-specific monster classes
Simple stat changes	Modify Monster.xml stats directly

Related Systems

For comprehensive monster control:

• MonsterAIUnit.xml - AI Unit definitions that rules override to

• MonsterAIGroup.xml - Default AI Unit assignments (BasicAI)

• Monster.xml - Stats, aggression (ViewRange), movement patterns

• MonsterSkill.xml - Skills with conditional triggers (HP-based)

• MonsterSetBase.xml - Spawn timing and locations