In a 3D environment context, Recast.js is meant to be used with a file describing a scene geometry. Using the recastnavigation C++ library compiled to WebAssembly, it will deduce a navigation mesh: a set of polygons on which your characters can move.

Once this navigation mesh is computed, it is possible to use built-in pathfinding operations like "find the shortest path between point A and point B", taking into account obstacles, slopes, and off-mesh connections.

If you decide to use it to animate your scene characters aka "agents", it also provides a complete crowd system capable of managing all your agents movements using per-agent settings (speed, radius, ...).

play the demo

Navmesh building

• load any mesh in .obj format
• compute its navigation mesh with configurable parameters (cell size, agent height, slope angle, ...)
• build a solo navmesh or a tiled navmesh (better for large scenes and dynamic obstacles)
• save and load the computed navmesh to skip recomputation

Pathfinding

• find the shortest path between two points
• find the nearest navigable point or polygon to any world position
• get a random point guaranteed to be on the navmesh

Obstacles & navigation areas

• place and remove temporary obstacles
• define off-mesh connections (jump links, doors, portals)
• assign polygon flags and group them into zones to influence pathfinding
• with instant effect, no rebuild needed

Crowd simulation

• add agents to the navmesh and drive them with a full crowd simulation
• update agents individually (speed, radius, separation weight, ...)

Is it for WebGL, Three.js or Babylon.js?

It is designed to work alongside any WebGL software but it is completely library agnostic. It only manages a mesh and its properties — it has no opinion on how you render things.

It runs in Node.js, in the browser, and in Web Workers. Included tests and demos use Three.js, though.

Demos

Browser demos are available in tests/browser/:

• webgl — WebGL rendering, crowd, obstacles and offmeshs links
• doors — off-mesh connections for door traversal
• worker — running recast inside a Web Worker (work in progress)