NavMesh not updating walkable areas at runtime

[ColdFusion-9k]

Hi,
I'm dynamically generating meshes at runtime and updating the NavMesh accordingly. When I set a generated mesh's NavMeshModifier to "Not Walkable," the NavMesh correctly updates to exclude this area. However, if i set the same mesh object's modifier to "Walkable," the NavMesh fails to incorporate this area into the navigation mesh.
Is there a way to make it work?

[h8man]

Hello,

It seems I can't reproduce issue. Please share your NavMesh setup (print screens and descreption)

Did you checked demo project?

[ColdFusion-9k]

Hi,
I have recreated the issue in the demo project.
In the SampleSceneRuntime i have created 3 objects:
1.WalkableSquare - just a default square that has a walkable area
2.UnwalkableSquare - the default square with an unwalkable modifier
3.WalkablePolygonMesh - an Object that will construct a mesh on Start().
3.UnwalkablePolygonMesh - an Object that will construct a mesh on Start().
The first two just to make sure that children of Grid will be processed for mesh navigation.
The polygons are for testing the actual issue.
At first both polygons didn't register.
After I moved them to be children of the NavMesh object (or set the object to collect all object) they were calculated.
The result as you can see that the unwalkable polygon is actually changing the nav mesh but the walkable polygon does not. There should be a small walkable NavMesh area on the triangle points outside the SecretColider area.
I've attached the screenshots of the issue and mesh generation description and code.

This is how the NavMesh looks after running the scene:

Definition of the WalkablePolygonMesh:

the mesh generation script is pretty basic:
`public class PolygonMeshGenerator : MonoBehaviour
{
void Start()
{

        var points = new Vector3[3];
        points[0] = new Vector3(0, 0, 0);
        points[1] = new Vector3(10, 0, 0);
        points[2] = new Vector3(10, 10, 0);
        // Create a new mesh
        Mesh mesh = new Mesh();
        // Define triangles (assuming the polygon is convex)
        int[] triangles = new int[3];
        triangles[0] = 0;
        triangles[1] = 1;
        triangles[2] = 2;

        // Assign data to the mesh
        mesh.vertices = points;
        mesh.triangles = triangles;

        // Optionally, calculate normals and bounds
        mesh.RecalculateNormals();
        mesh.RecalculateBounds();

        // Assign the mesh to the MeshFilter
        GetComponent<MeshFilter>().mesh = mesh;

        // Assign a material for rendering (you can adjust this to your liking)
        GetComponent<MeshRenderer>().material = new Material(Shader.Find("Sprites/Default"));
    }
}`

[h8man]

Hi,

Yeah, I reproduced the issue. The problem is that NavMeshPlus doesn't have special logic for 3D Mesh, but 2d object only (Collider2D, Tilemap, SpriteRenderer). So PolygonMeshGenerator goes straight though Unity pipeline and somehow doesn't effect NavMesh. So we need to dig deeper into Unity itself

Why would you use 3D Mesh is the first place? Is this issue reproduced with Sprites?

[ColdFusion-9k]

Hi,

1. If 3d meshes don't affect NavMesh how is it that the unwalkable mesh does affect the NavMesh?
2. weirdly enough i ran my the demo project another time and now the unwalkable mesh doesn't affect the NavMesh for some reason. It still works the same in my original project.
3. I need to create areas with arbitrary shape that the agents can navigate on. Basically procedural generation of islands.
   It seemed easier to generate the outline of the islands and create a mesh.
4. i tried creating a few sprites to test this, a 9-sliced sprite and that doesn't seem to affect the NavMesh either. Not sure why the unwalkable mesh that was excluded from the NavMesh earlier is not excluded now. In the screen shot i have highlighted the walkable 9-sliced sprite.

[h8man]

1. I meant it doesn't work as expected.
2. Its not sprite that matters, but sprite's mesh

NavMeshPlus is just a wrapper to extract meshes from 2d objects, if you already have 3d mesh you can utilize ai.navigation components.

Meanwhile I'll keep digging.

[ColdFusion-9k]

Ok,
I see that the regular nav mesh works for me.
Thank you so much for your help.

[h8man]

Lets keep it open till I found what's going on.