In a game context, Recast.js is meant to be used with a file describing a scene geometry. Using the recastnavigation library, 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 various variables like 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, ...)

• load any mesh in .obj format
• compute and extract its navigation mesh with options
• save this navigation mesh
• load this blob without recompute it
• find a random point guaranteed to be navigable
• find the nearest path from one point to another
• place obstacles with a radius
• add agents on the navigation mesh
• make them move with their own speed

It is designed to work along a WebGL software but it's completely library agnostic. It only manages a mesh and its properties.

Included tests and demos use Three.js, though.