NavMesh Agent component in Unity - Step-by-Step Execution

Concept Flow - NavMesh Agent component

Start

↓

Set Destination

↓

Calculate Path on NavMesh

↓

Move Agent Along Path

↓

Check if Destination Reached

↓

Continue Moving

↓

Update Position

↓

Repeat Until Destination Reached

The NavMesh Agent moves step-by-step towards a set destination by calculating a path on the NavMesh and updating its position until it reaches the target.

Execution Sample

Unity

NavMeshAgent agent;

void Start() {
  agent = GetComponent<NavMeshAgent>();
  agent.SetDestination(target.position);
}

void Update() {
  if (!agent.pathPending && agent.remainingDistance <= agent.stoppingDistance) {
    agent.isStopped = true;
  }
}

This code sets a destination for the NavMesh Agent and stops it when it reaches close enough to the target.

Execution Table

Step	Agent Position	Destination	Path Calculated	Remaining Distance	Action	Agent State
1	(0,0,0)	(10,0,10)	Path calculated	14.14	Start moving	Moving
2	(1,0,1)	(10,0,10)	Following path	12.73	Continue moving	Moving
3	(3,0,3)	(10,0,10)	Following path	9.90	Continue moving	Moving
4	(6,0,6)	(10,0,10)	Following path	5.65	Continue moving	Moving
5	(8,0,8)	(10,0,10)	Following path	2.83	Continue moving	Moving
6	(9.5,0,9.5)	(10,0,10)	Following path	0.71	Continue moving	Moving
7	(10,0,10)	(10,0,10)	At destination	0	Stop agent	Stopped

💡 Agent reached destination; remaining distance is 0, so agent stops.

Variable Tracker

Variable	Start	After 1	After 2	After 3	After 4	After 5	After 6	Final
Agent Position	(0,0,0)	(1,0,1)	(3,0,3)	(6,0,6)	(8,0,8)	(9.5,0,9.5)	(10,0,10)	(10,0,10)
Remaining Distance	14.14	12.73	9.90	5.65	2.83	0.71	0	0
Agent State	Idle	Moving	Moving	Moving	Moving	Moving	Stopped	Stopped

Key Moments - 3 Insights

Why does the agent keep moving even when the remaining distance is small but not zero?

Because the agent stops only when the remaining distance is less than or equal to the stopping distance (see step 6 in execution_table), not necessarily zero.

What happens if the path is not calculated yet when checking remaining distance?

The agent waits (pathPending is true) and does not move until the path is ready, ensuring smooth movement (refer to code in execution_sample).

Why does the agent stop exactly at the destination position?

Because when remainingDistance reaches zero, the agent sets isStopped to true, halting movement (see step 7 in execution_table).

Visual Quiz - 3 Questions

Look at the execution_table, what is the agent's position at step 4?

A (8,0,8)

B (3,0,3)

C (6,0,6)

D (9.5,0,9.5)

💡 Hint

Check the 'Agent Position' column at step 4 in the execution_table.

At which step does the agent stop moving?

A Step 7

B Step 6

C Step 5

D Step 3

💡 Hint

Look at the 'Agent State' column in execution_table to find when it changes to 'Stopped'.

If the stoppingDistance was increased, how would the agent's stopping step change?

A Agent would stop later, closer to destination

B Agent would stop earlier, at a larger remaining distance

C Agent would never stop

D Agent's path would change

💡 Hint

Refer to the condition in the code where agent stops when remainingDistance <= stoppingDistance.

Concept Snapshot

NavMesh Agent moves on a NavMesh towards a set destination.
Use SetDestination() to tell agent where to go.
Agent calculates path and moves step-by-step.
Agent stops when within stoppingDistance of target.
Check pathPending and remainingDistance to control movement.

Full Transcript

The NavMesh Agent component in Unity moves a game object along a path calculated on a NavMesh towards a destination. First, you set the destination using SetDestination(). The agent calculates the path and starts moving. Each update, the agent's position changes closer to the target, and the remaining distance decreases. When the remaining distance is less than or equal to the stopping distance, the agent stops moving. The code checks if the path is ready before moving to avoid errors. This process repeats until the agent reaches the destination and stops.