AI Basics (NavMesh) In Unity

NavMesh (Navigation Mesh) is a simplified map of your scene that tells AI where it can walk. Unity's NavMesh system calculates paths and moves characters around obstacles automatically.

AI moves around walls and obstacles
Finds shortest path automatically
No need for complex pathfinding code

1. Setting Up NavMesh

Step 1: Open Navigation window: Window - AI - Navigation.

Step 2: Mark objects as walkable or not

Select floor/ground objects
Check "Navigation Static" in Inspector

Step 3: Mark obstacles (walls, trees, rocks)

Select obstacle objects.
Check "Navigation Static".
Set Navigation Area to "Not Walkable".

Step 4: Bake the NavMesh.

Navigation window - Bake tab.
Click "Bake" button.

The blue area appears in Scene view showing where AI can walk.

2. Adding NavMesh Agent to Enemy

The NavMesh Agent component moves the enemy along the calculated path.

Step 1: Select your enemy GameObject.

Step 2: Add Component - NavMeshAgent.

Important settings:

Setting	Value	What it does
Speed	3.5	Controls movement speed
Angular Speed	120	Controls how fast the agent turns
Acceleration	8	Determines how quickly it reaches full speed
Stopping Distance	1	Distance from target where the agent stops
Radius	0.5	Defines size for obstacle avoidance
Height	2	Sets the height of the agent

3. Making Enemy Follow Player

Example:

using UnityEngine;
using UnityEngine.AI;
public class EnemyAI : MonoBehaviour
{
    public Transform player;
    private NavMeshAgent agent;
    void Start()
    {
        agent = GetComponent<NavMeshAgent>();
        
        // Find player by tag if not assigned
        if (player == null)
        {
            player = GameObject.FindGameObjectWithTag("Player").transform;
        }
    }
    void Update()
    {
        // Set enemy destination to player position
        agent.SetDestination(player.position);
    }
}

Output:

agent.SetDestination() tells the enemy where to go. NavMeshAgent automatically finds the path and moves there.

NavMesh vs Simple Movement

Feature	NavMesh	Simple Movement
Pathfinding	Automatic pathfinding	Manual movement logic required
Obstacle Handling	Automatically avoids obstacles	Requires custom handling
Use Case	Best for complex environments (AI, enemies)	Best for simple/open areas
Performance	Slightly heavier	Lightweight and faster
Implementation	Easier for navigation logic	Requires more manual coding

Common NavMesh Issues

Enemy not moving check NavMeshAgent is attached and NavMesh is baked.
Enemy stuck on walls increase Radius in NavMeshAgent.
Enemy goes through obstacles re-bake NavMesh after scene changes.
No blue area visible open Navigation - Bake and generate NavMesh.