Modify Navmesh dynamically

Unity Courses Talk
1

Is it possible to add or modify a navmesh programatically.

For example, if an enemy is chasing and you close a gate, can you set the gate as blocking so the enemy looks for another route.?

2

I’m not sure but I think since unity 5.6 it is possible.

3

It wasn’t possible before, but in Unity 5.6 it apparently can be done (GitHub, Documentation, Forum).

I ran across this code snippet and altered it a bit – adding/removing works, but I’d be cautious, since the whole functionality still seems like work-in-progress.

using System.Collections.Generic;
using UnityEngine;
using UnityEngine.AI;

public class NavMeshOwner : MonoBehaviour {

    [SerializeField] LayerMask navMeshLayers;
    [SerializeField] Vector3 upDirection = Vector3.up;

    NavMeshDataInstance navMeshDataInstance;

    void OnEnable() {
        // Create new NavMesh whenever the script is enabled            
        CreateNavMesh();
    }
    void OnDisable() {
        // Delete current NavMesh whenever the script is disabled
        RemoveNavMesh();
    }

    private void CreateNavMesh() {
        List<NavMeshBuildSource> buildSources = new List<NavMeshBuildSource>();

        NavMeshBuilder.CollectSources(transform, navMeshLayers, NavMeshCollectGeometry.RenderMeshes, 0, new List<NavMeshBuildMarkup>(), buildSources);

        NavMeshData navData = NavMeshBuilder.BuildNavMeshData(NavMesh.GetSettingsByID(0), buildSources,
                                new Bounds(Vector3.zero, new Vector3(10000, 10000, 10000)), Vector3.down,
                                Quaternion.Euler(upDirection)
                                );

        navMeshDataInstance = NavMesh.AddNavMeshData(navData);
    }

    private void RemoveNavMesh() {
        navMeshDataInstance.Remove();
    }
}

Just slap it on an object and set its layer. It roughly works like this:

But as I was sifting through the documentation, I found something which might be more suitable for what you want to do – NavMesh Obstacle. :slight_smile: