Importing A Unity Navmesh

The Quantum navmesh generation is build on top of the Unity navmesh pipeline. A Unity navmesh triangulation is imported and baked into Quantum navmesh binary format.

The baking writes world positions into the Quantum navmesh because only navmeshes located in the origin are supported. Similar to Quantum physics it is encouraged that gameplay takes place near the origin to prevent fixed point precision issues.

Importing A Unity Navmesh

• Add the AI Navigation package com.unity.ai.navigation to the Unity project using the Unity Package Manager > Unity Registry.

  

• Create and set up a Unity navmesh surface.

  

• Create a new GameObject under the map QuantumMapData and add a QuantumMapNavMeshUnity script.

  

• Add the surface GameObject to the Nav Mesh Surfaces list.

  

• Select the map object and enable Everything on the Bake All Mode options. Then press Bake All. A navmesh imported message will be logged on the console.

  Imported Unity NavMesh 'Navmesh', cleaned up 7 vertices, found 1 region(s), found 0 link(s)
  

• The Quantum navmesh asset is baked into two asset files. The navmesh asset and a second binary data asset (_data suffix), which are placed next to the map asset.

  

• After baking the navmesh asset is referenced in the QuantumMapData script under Nav Mesh Links.

  

• Select the map object to show the Quantum navmesh gizmos. Open the Quantum Gizmo Overlay Menu to toggle different types of gizmo drawing (right-click on the scene tab > Overlay Menu > Quantum Gizmos).

  

• Optionally toggle navmesh building on different auto build mode triggers in QuantumEditorSettings.

  

• Add the Quantum.Core.NavigationSystem to the SystemsConfig that is set on the RuntimeConfig when starting the game. The default config has the system correctly added and enabled.

  

Import Settings

The conversion from a Unity navmesh to a Quantum navmesh uses import settings that can be customized using the QuantumMapNavMeshUnity script.

Navmesh Settings on the Map

The QuantumMapData script has two relevant navmesh settings: the serialization type and the navmesh grid and world size. Both settings get applied and copied to the navmesh asset during baking.

NavMesh Serialize Type

The setting controls how much of the navmesh asset is serialized with the asset and how much is generated at load time. It can be used to reduce the asset size, which could be interesting when the asset is created and send to clients at runtime (see Custom Navmesh Generation).

NavMesh Area and Grid

Gizmos for NavMesh Area and NavMesh Grid are rendered to the scene when toggled on in the Quantum Navmesh Overlay Menu.

The grid is configured by selecting the QuantumMapData script under the NavMesh Settings headline. The number of grid cells in X and Y/Z direction and the grid node size (cell dimension in Unity units per cell) result in the overall grid size.

The navmesh grid area needs to encompass the complete navmesh (blue box on the left screenshot).

The grid cells (yellow square on the right screenshots) require a reasonable size to not include too many individual navmesh triangles. It's a trade-of between navmesh data size and performance. The smaller the cells the larger the data structure but less triangles need to be touched during pathfinding.

Even if the navmesh world position is not near the origin it still has to be inside the grid area.

Custom Navmesh Baking Callback

The navmesh baking process can be extended by callbacks extending the MapDataBakerCallback class.

Add the following script into QuantumUser/Editor.

The QuantumMapBakeAssembly attribute is required for the baking process to find the callbacks.

C#

[assembly: Quantum.QuantumMapBakeAssembly]

namespace Quantum.Editor
{
  using System.Collections.Generic;
  using UnityEngine;

  public class NavmeshBakeCallback : MapDataBakerCallback
  {
    public override void OnBeforeBakeNavMesh(QuantumMapData data)
    {
      // Before any navmesh baking takes place.
    }

    public override void OnCollectNavMeshBakeData(QuantumMapData data, List<NavMeshBakeData> navMeshBakeData)
    {
      // Unity navmesh surfaces have been imported and bake data is already filled out.
      Debug.Log($"Found {navMeshBakeData.Count} navmesh bake data");
    }


    public override void OnCollectNavMeshes(QuantumMapData data, List<NavMesh> navmeshes)
    {
      // Quantum navmesh have been baked.
    }

    public override void OnBakeNavMesh(QuantumMapData data) { 
      // Quantum navmeshes have been saved to assets.
    }

    // abstract methods have to be implemented but not needed here
    public override void OnBake(QuantumMapData data) { }
    public override void OnBeforeBake(QuantumMapData data) { }
  }
}