MonsterAIRule.xml

Defines conditional rules that temporarily override a monster class's active AI Unit based on calendar date and time. While a rule is active, every live monster of the target class switches from its BasicAI to the rule's Unit until the rule expires.

File Location#

Data/Monster/MonsterAIRule.xml

Dependencies#

How It Works#

1. The AI dispatcher walks the rule list on every AI tick.
2. Each rule is tested against the current server clock (and, when relevant, server events).
3. If a rule is valid and past its WaitTime but still inside WaitTime + ContinuanceTime, the target class is tagged with the rule's Unit.
4. On the next AI update, every live monster of that class has its CurrentAI switched to that Unit; its BasicAI is preserved untouched.
5. When no rule is active for the class, monsters fall back to BasicAI from MonsterAIGroup.xml.

Current Status#

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

Configuration Structure#

Rule Attributes#

Condition Types#

Important Behavior#

Timing Logic#

condition first TRUE -> wait [WaitTime]s -> override ACTIVE for [ContinuanceTime]s -> override EXPIRES

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

• 00:00:00 - condition becomes true
• 00:00:10 - override activates (10 s wait elapsed)
• 01:00:10 - override expires (3600 s duration elapsed)

Both WaitTime and ContinuanceTime are in seconds. ContinuanceTime="60" means one minute, not one hour.

Date/Time Matching#

• All non-wildcard fields must match simultaneously for the condition to be true.
• WeekDay is tested first. A mismatch short-circuits the rule as invalid for the current tick.
• Month, Day, Hour, Minute each build a "valid from" timestamp when their field differs from the current clock. The rule stays valid from that timestamp through WaitTime + ContinuanceTime past it.
• Matching is minute-precision. Firing resolution is the AI dispatcher tick (sub-second).

Multiple Rules Per Class#

Rules are evaluated in file order and all write to the same per-class override slot:

• The last rule in the file that touches a given Class determines the outcome for that class.
• If the last-listed rule for a class is valid, its Unit is applied.
• If the last-listed rule for a class is invalid (its condition is false or outside the timing window), the override slot is cleared even if an earlier rule for the same class was valid.

Order rules for the same class so the one you actually want to win is listed last, or keep one rule per class to avoid the overwrite.

Fallback to BasicAI#

When no active rule targets a monster's class, that monster uses its BasicAI assigned by MonsterAIGroup.xml. The override never modifies BasicAI itself; it only swaps the runtime CurrentAI pointer.

Performance#

Every rule is checked against the clock on every AI tick, and every live monster of an overridden class has its CurrentAI pointer rewritten on every AI tick. Keep the rule list small. The loader caps it at 200 entries.

Examples#

<MonsterAIRule>
  <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>

<MonsterAIRule>
  <Rule
    Number="2"
    Class="20"
    Description="Saturday night White Wizard event"
    Unit="205"
    Condition="1"
    WaitTime="0"
    ContinuanceTime="14400"
    Month="*"
    Day="*"
    WeekDay="7"
    Hour="20"
    Minute="0"
  />
</MonsterAIRule>

<MonsterAIRule>
  <Rule
    Number="3"
    Class="3"
    Description="Evening peak aggression"
    Unit="150"
    Condition="1"
    WaitTime="0"
    ContinuanceTime="14400"
    Month="*"
    Day="*"
    WeekDay="*"
    Hour="18"
    Minute="0"
  />
</MonsterAIRule>

<MonsterAIRule>
  <Rule
    Number="4"
    Class="50"
    Description="Christmas Elf event (delayed start)"
    Unit="300"
    Condition="1"
    WaitTime="3600"
    ContinuanceTime="82800"
    Month="12"
    Day="25"
    WeekDay="*"
    Hour="0"
    Minute="0"
  />
</MonsterAIRule>

Common Issues#

Use Cases#

Time-Based Events#

• Night aggression: lower DelayTime Unit during dark hours
• Weekend bosses: swap to boss-behaviour Units on Saturday/Sunday
• Hourly rotations: multiple classes each with their own schedule

Seasonal Events#

• Halloween behaviour on October 31
• December festive patterns
• Anniversary overrides

Dynamic Difficulty#

• Peak-hour challenge: harder Units during prime-time
• Off-peak: easier Units overnight

When NOT to Use MonsterAIRule#

Related Systems#

• MonsterAIUnit.xml - AI Unit definitions that rules override to
• MonsterAIAutomata.xml - state machine rules used by each Unit
• MonsterAIElement.xml - per-state actions used by each Unit
• MonsterAIGroup.xml - default AI Unit assignments (BasicAI)
• Monster.xml - stats, aggression (ViewRange), movement patterns
• MonsterSkill.xml - HP-gated skill triggers
• MonsterSetBase - spawn timing and locations