Post
A simplified invisible surface draped over your level that tells AI exactly where it can and cannot walk.
A navigation mesh (navmesh) is a collection of convex polygons that define the walkable surfaces in a game environment. Instead of pathfinding on a grid of tiles, AI agents pathfind across these polygons, which represent the actual traversable geometry of the level. Navmeshes are more memory-efficient than grids, handle complex 3D environments naturally, and allow agents of different sizes by shrinking the walkable area based on agent radius. They can be generated automatically from level geometry using tools built into engines like Unity, Unreal, and Godot. Off-mesh links connect disconnected areas -- jump points, ladders, teleporters -- letting AI know about special traversal options. Dynamic obstacles can carve holes in the navmesh in real time, allowing AI to path around newly placed objects.
Example
Unreal Engine's navigation system generates navmeshes automatically from level geometry and supports real-time dynamic obstacles. In Fortnite, when players build structures, the navmesh updates dynamically so AI opponents can pathfind around player-constructed walls and ramps without getting stuck.
Why it matters
Navigation meshes are the bridge between pathfinding algorithms and the actual game world. Without them, AI would be stuck on simple grid-based movement that cannot handle slopes, multi-level buildings, or irregular terrain. They make believable NPC navigation possible in complex 3D environments.
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