# G2 — Event System Mastery > **Category:** guide · **Engine:** RPG Maker · **Related:** [E1 Architecture Overview](../architecture/E1_architecture_overview.md) · [G1 Plugin Development](G1_plugin_development.md) · [R1 Database Configuration](../reference/R1_database_configuration.md) --- ## Overview The event system is RPG Maker MZ's primary gameplay scripting tool. Nearly everything that isn't database-driven — NPC dialogue, cutscenes, puzzles, quest logic, map transitions — is built with events. Understanding event triggers, page conditions, command flow, and common events is essential for building anything beyond a basic battle-and-explore loop. --- ## Map Events A map event is an entity placed on a specific tile in the map editor. Each event has one or more **pages**, evaluated right-to-left (highest page number first). The first page whose conditions are met becomes the active page. ### Page Conditions Each page can require any combination of: | Condition | What It Checks | |-----------|---------------| | **Switch** | A global switch is ON | | **Variable** | A global variable meets a numeric comparison (≥, ≤, =, etc.) | | **Self Switch** | A per-event switch (A, B, C, or D) is ON | | **Item** | The party possesses a specific item | | **Actor** | A specific actor is in the party | > **Self switches** are scoped to the individual event on the individual map. They're ideal for one-time interactions: set Self Switch A to ON after the player opens a chest, and page 2 (with the "already opened" graphic) becomes active. ### Multi-Page Pattern: NPC Quest ``` Event: Old Man (3 pages, evaluated right-to-left) Page 3 — Condition: Switch [Quest Complete] is ON → "Thank you for saving the village!" → Graphic: happy old man Page 2 — Condition: Switch [Quest Accepted] is ON → "Have you defeated the wolves yet?" → Conditional Branch: Variable [Wolves Killed] ≥ 5 → "Wonderful! Take this reward." → Change Items: +1 Magic Sword → Control Switches: [Quest Complete] = ON → Else → "Please hurry..." Page 1 — No conditions (default/fallback) → "The wolves are terrorizing our village. Will you help?" → Show Choices: Yes / No → Yes: Control Switches: [Quest Accepted] = ON → No: "Please reconsider..." ``` --- ## Trigger Types The trigger determines **when** an event's active page executes: | Trigger | Behavior | Use Case | |---------|----------|----------| | **Action Button** | Fires when the player presses the confirm key while facing the event | NPCs, signs, chests, doors | | **Player Touch** | Fires when the player steps onto the event's tile | Traps, transfer zones, cutscene triggers | | **Event Touch** | Fires when the event moves onto the player's tile | Chasing enemies, patrol guards | | **Autorun** | Fires immediately and continuously; **freezes player input** | Cutscenes, forced dialogue, one-time map setup | | **Parallel** | Fires continuously alongside normal gameplay; **player can still move** | Background timers, ambient systems, conditional checks | ### Autorun vs. Parallel — Critical Differences **Autorun** blocks all player input and other events until it completes or the page becomes inactive (e.g., by flipping a switch that changes the active page). Always include a way for the autorun to "finish" — typically by changing a switch on its last line so the page condition no longer holds. ``` Page 1 — Trigger: Autorun, Condition: Switch [Intro Played] is OFF → Fade Out Screen → Show Text: "One year has passed..." → Fade In Screen → Control Switches: [Intro Played] = ON ← disables this page ``` **Parallel** runs its commands every frame (~60 times per second) while the player retains full control. This makes it powerful for monitoring game state but dangerous for performance. --- ## Common Events Common events are global events not tied to any map. They live in the Database → Common Events tab and can be called from anywhere. ### Three Start Modes | Mode | Behavior | When to Use | |------|----------|-------------| | **None** | Must be called explicitly via "Common Event" command or item/skill usage | Reusable utility routines (heal party, open shop, show tutorial) | | **Autorun** | Runs automatically when its switch is ON; blocks input | Global cutscenes that can trigger from any map | | **Parallel** | Runs automatically when its switch is ON; player keeps control | Global monitoring: day/night cycles, quest trackers, HUD updates | ### Calling a Common Event ``` Event Command: Common Event → [Common Event name] ``` Common events with trigger "None" can also be invoked when a **skill** or **item** is used (set in the Database under the skill/item's "Common Event" field). This is how custom menu abilities work — a "Camping" skill that triggers a common event for rest/save/cook. --- ## Parallel Events: Performance and Safety Parallel events repeat their entire command list every frame. A careless parallel event can cause severe lag. ### Performance Rules 1. **Use Wait commands.** A `Wait: 1 frame` at the end of a parallel event gives the engine a full frame to process everything else before re-running the event. For checks that don't need frame-perfect timing, `Wait: 10 frames` or `Wait: 30 frames` is better. 2. **Use Conditional Branches to skip work.** If a parallel event only needs to act when a condition is met, wrap the expensive actions inside a Conditional Branch so the engine only evaluates the cheap condition check each frame. ``` Parallel event — Quest Tracker: ◆ Conditional Branch: Variable [Wolves Killed] ≥ 5 ◆ Control Switches: [Quest Complete] = ON ◆ Erase Event ← or disable via self switch to stop the parallel ◆ End ◆ Wait: 15 frames ← only check once every quarter-second ``` 3. **Use Labels and Jump-to-Label for loops.** Instead of letting the entire command list restart from the top, use labels to create a tight inner loop that skips initialization logic on subsequent iterations. 4. **Limit active parallel events.** On any given map, avoid having more than 3–4 parallel events running simultaneously. Each one consumes interpreter cycles. ### Important Limitation Autorun and Parallel common events only execute when the **Map Screen** is displayed. They do **not** run during battle, in menus, or during other scenes. If you need logic during battle, use troop event pages (in the Troops tab) or plugins. --- ## Useful Event Commands ### Variables and Switches ``` Control Switches: [Switch Name] = ON/OFF Control Self Switch: A = ON Control Variables: [Var] = value / += / -= / *= / random(min, max) Control Variables: [Var] = Game Data (map ID, party size, gold, etc.) ``` ### Flow Control ``` Conditional Branch: Switch / Variable / Self Switch / Timer / Actor / etc. → (true branch) Else → (false branch) End Loop → (commands repeat until Break Loop) Break Loop ``` ### Movement and Timing ``` Set Movement Route: [target] → Move Down / Turn Left / Change Speed / etc. → Options: Wait for Completion, Skip if Can't Move, Repeat Wait: N frames ``` ### Screen Effects ``` Fade Out Screen / Fade In Screen Tint Screen: (R, G, B, Gray) over N frames Flash Screen: (R, G, B, Strength) over N frames Shake Screen: Power, Speed, Duration ``` ### Transfer and Map Control ``` Transfer Player: [Map], (X, Y), Direction, Fade Type Scroll Map: Direction, Distance, Speed ``` --- ## Advanced Patterns ### Self-Disabling Autorun (One-Time Cutscene) The most important pattern in RPG Maker. Every autorun must disable itself, or the game freezes in an infinite loop. ``` Page 1 — Trigger: Autorun, Condition: Self Switch A is OFF ◆ (cutscene commands) ◆ Control Self Switch: A = ON ← switches to Page 2 Page 2 — Condition: Self Switch A is ON ◆ (empty, or a different graphic/interaction) ``` ### Proximity Detection Without Parallel Events Instead of running a parallel event to check distance, use a transparent event with **Player Touch** trigger placed on tiles around the NPC. This costs zero processing until the player steps on the trigger tile. ``` Invisible event at (NPC_X - 3, NPC_Y) — Trigger: Player Touch ◆ Set Movement Route: NPC → Turn Toward Player ◆ Show Balloon: NPC → Exclamation ``` ### Chained Common Events for Modular Dialogue Break complex dialogue trees into small common events and call them from each other: ``` Common Event: "Shop Greeting" ◆ Show Choices: Buy / Sell / Talk / Leave → Buy: Common Event → "Shop Buy Menu" → Sell: Common Event → "Shop Sell Menu" → Talk: Common Event → "Shop Chat" → Leave: (end) ``` ### Variable-Driven Difficulty Scaling Use a global variable to adjust encounters dynamically: ``` Parallel Common Event — Difficulty Scaler: ◆ Conditional Branch: Variable [Battles Won] ≥ 20 ◆ Control Variables: [Enemy Boost] = 150 (percent) ◆ Else: Conditional Branch: Variable [Battles Won] ≥ 10 ◆ Control Variables: [Enemy Boost] = 125 ◆ Else ◆ Control Variables: [Enemy Boost] = 100 ◆ End ◆ Wait: 300 frames ← only recalculate every 5 seconds ``` (The `[Enemy Boost]` variable is read by plugin-modified enemy stats or troop event pages.) --- ## Common Pitfalls 1. **Autorun without self-disable** — the game locks up because the autorun restarts infinitely. Always flip a switch or self switch on the last line. 2. **Parallel events without Wait** — runs 60 times per second with full command processing. Even a `Wait: 1` helps. Longer waits are better when frame-precision isn't needed. 3. **Too many parallel events on one map** — each parallel event gets its own interpreter instance. More than 4–5 active parallels can cause noticeable lag, especially on mobile. 4. **Forgetting page evaluation order** — pages are checked highest-to-lowest. If page 3's conditions are met, pages 2 and 1 are ignored entirely. Plan your conditions so they're mutually exclusive or properly ordered. 5. **Using Autorun for background monitoring** — Autorun blocks the player. Use Parallel for anything that should run while the player is free to move. 6. **Common events expecting battle-time execution** — Autorun/Parallel common events only run on the Map scene. For battle logic, use Troop event pages or Battle Processing commands.