Skip to content

Enemy AI

Difficulty: Intermediate
Method A (Enemy AI prefab): ~10 minutes
Method B (Modular system): ~30 minutes

Build an enemy that detects the player, chases them, and attacks when close enough. This tutorial covers two approaches: a single prefab node and a modular pipeline built from individual AI nodes.

What you'll build

An enemy object that:

  • Idles until the player enters a configurable detection radius and field of view
  • Transitions between IDLE, CHASE, and ATTACK states automatically
  • Moves toward the player when detected
  • Attacks when within attack range

Prerequisites

  • Completed Getting Started
  • A scene with a player object (completing My First FPS first is recommended)
  • A scene with an enemy object — any mesh works

Scene setup

Both methods use the same base configuration.

Player object

Must exist in the scene with a recognizable name. The examples below use player.

Enemy object

  • Any mesh (Capsule, Cube, or a character mesh)
  • Physics type: Dynamic (or Character for more precise collision)
  • This object will receive the RNC component

Method A — Enemy AI (prefab)

Use when: you need a functional enemy quickly, the default behaviors match your design, or you are prototyping combat before committing to a final AI architecture.

Limitation: behaviors are fixed. Adding custom states — patrol, cover, flee, or a Behavior Tree — requires switching to Method B.

Step 1 — Create the NodeTree

Select the enemy object. Open the Node Editor, click New.

Step 2 — Add the nodes

  • Shift + A → EVENT → On Update
  • Shift + A → AI → Enemy AI

Step 3 — Configure Enemy AI

Property Value Notes
Target player Name of the player object in the scene
Detection Radius 15.0 Distance in units to detect the player
Field of View 120.0 Degrees of peripheral vision
Chase Speed 4.0 Movement speed while chasing
Attack Range 2.0 Distance at which the enemy attacks
HP 100 Enemy hit points

Step 4 — Connect

[On Update] ──Exec──► [Enemy AI]
                          Target=player
                          Detection Radius=15.0
                          Field of View=120.0
                          Chase Speed=4.0
                          Attack Range=2.0
                          HP=100

Step 5 — Register the component

Info Componente → Add RNC Component → Assign NodeTree (same flow as Getting Started).

Step 6 — Play

Press P. The enemy will idle until the player enters its detection radius, then switch to CHASE state and finally ATTACK state when close enough.

Method B — Modular system

Use when: you need custom states, multiple behavior variants, Behavior Tree integration, or per-enemy tuning of individual subsystems.

Method B exposes the same underlying logic as Method A, but as individual nodes. Each node reads and writes named attributes on self using a shared ai_* prefix (e.g., self.ai_state, self.ai_dist, self.ai_can_see). Nodes must run in a fixed order — define that order through your exec chain.

!!! note "Simplified modular enemy" This tutorial uses Seek for movement (direct line movement toward the target). Add Navigation Pathfinder + Navigation Follow Path when you need obstacle-aware pathfinding with waypoints.

The pipeline

[On Update]
    │
    ├─► [Enemy Perception]   → writes ai_can_see, ai_dist, ai_target_pos
    │
    ├─► [Damage Receiver]    → writes ai_hp, ai_is_dead
    │
    ├─► [AI State Machine]   → reads ai_can_see, ai_dist; writes ai_state
    │
    └─► [Enemy Decision]     → branches on ai_can_see
            │
            ├─ Visible ──► [Seek] → [Enemy Rotation] → [Enemy Combat] → [Enemy Animation]
            │
            └─ Hidden  ──►         [Enemy Rotation]                   → [Enemy Animation]

Step 1 — Create the NodeTree

Select the enemy object, click New in the Node Editor.

Step 2 — Add all nodes

Add each node with Shift + A:

Node Category
On Update EVENT
Enemy Perception AI
Damage Receiver AI
AI State Machine AI
Enemy Decision AI
Seek AI
Enemy Rotation AI
Enemy Combat AI
Enemy Animation AI

Step 3 — Configure each node

Enemy Perception:

Property Value
Target player
Detection Radius 15.0
Field of View 120.0

Damage Receiver:

Property Value
HP 100

AI State Machine — uses IDLE / CHASE / ATTACK / DEAD states by default. No additional configuration required for this setup.

Enemy Decision — branches execution based on ai_can_see. No configuration required.

Seek:

Property Value
Target player
Speed 4.0
Arrival Radius 2.0

Enemy Rotation:

Property Value
Speed 5.0

Enemy Combat:

Property Value
Attack Range 2.0
Attack Cooldown 1.5
Damage 10

Enemy Animation — configure with the action names from your project.

Step 4 — Connect the pipeline

Connect On Update → Enemy Perception → Damage Receiver → AI State Machine → Enemy Decision.

From Enemy Decision:

  • Visible output → Seek → Enemy Rotation → Enemy Combat → Enemy Animation
  • Hidden output → Enemy Rotation → Enemy Animation (the enemy continues rotating and animating even when the player is not detected)
[On Update] → [Enemy Perception]
                  → [Damage Receiver]
                  → [AI State Machine]
                  → [Enemy Decision]
                        │
                        ├─ Visible ──► [Seek] → [Enemy Rotation] → [Enemy Combat] → [Enemy Animation]
                        │
                        └─ Hidden  ──►          [Enemy Rotation]                  → [Enemy Animation]

Step 5 — Register the component

Info Componente → Add RNC Component → Assign NodeTree.

Step 6 — Play

Press P. Behavior is identical to Method A for the standard case.

Method A vs Method B

Criterion Method A (Enemy AI) Method B (Modular)
Setup time ~5 min ~25 min
Add patrol when idle Not possible Replace the Hidden branch with a Patrol node
Add custom AI states Not possible Configure additional states in AI State Machine
Multiple enemy variants Property differences only Each variant can use a different subset of nodes
Behavior Tree integration Not possible Replace Enemy Decision with BT nodes
Per-frame performance tuning No control Set Perception Interval on Enemy Perception
Debug individual behaviors No visibility Disconnect one node, insert Print to inspect ai_* state
Obstacle-aware navigation Built-in simplified Add Navigation Pathfinder + Navigation Follow Path

Next steps