NavMesh Build
Build a walkable navigation mesh from geometry.
What it does
Turns geometry into a walkable navigation mesh: a simplified polygon surface that pathfinding searches over. The geometry is voxelised, the walkable area is shrunk inward by the agent's radius so agents do not clip through walls, then the walkable boundary is segmented and extracted as a mesh.
The result is registered under a NavMesh name, so any Pathfind node can look it up and query routes across it. The original geometry passes through the Geometry Out pin unchanged.
When to use it
AI agents, characters or crowds pathing across level geometry without walking through walls or off ledges
A walkable surface that respects a slope limit and a step-up height, marking stairs and kerbs walkable and cliffs and steep ramps not
Several agent sizes sharing one level: build separate navmeshes with different names and radii, and point each Pathfind at the one that fits
| Parameter | Type | Default | What it does |
|---|---|---|---|
geometry | Collection | — | Mesh geometry to convert into a navigation mesh. |
mesh_id | String | "default" | NavMesh name — Pathfind nodes reference this to query the mesh. |
agent_radius | Number | 0.600 | Agent radius for navmesh erosion |
agent_height | Number | 2 | Agent height for clearance checks |
max_slope | Number | 45 | Maximum slope angle (degrees) for walkable surfaces |
max_climb | Number | 0.900 | Maximum step height for stairs/curbs |
resolution | Number | 64 | Grid resolution per axis for voxelization |
bounds_size | Number | 100 | Size of the voxelization bounding box |
opacity | Number | 1 | Layer opacity (0 = transparent, 1 = opaque). Editable, wirable, keyframable. |
Gotchas
Agent Radius does more than describe the agent: it erodes the walkable surface inward. Raise it for a wide agent and narrow gaps and doorways stop being walkable.
The navmesh is keyed by NavMesh Name, not by node identity. If two NavMesh Build nodes share a name, the later one to cook overwrites the earlier one's registration. Give each distinct navmesh its own name.
Bounds Size sets the voxelisation box the geometry is fit into. Geometry larger than the bounds is clipped from the navmesh. Raise Bounds Size, and Resolution to keep voxel detail, to match the level's scale.
Worked example
Wire the level geometry into Geometry.
Set NavMesh Name to something to reference later, e.g.
main_level.Set Agent Radius and Agent Height to match the character or vehicle that will walk the mesh.
Adjust Max Slope and Max Climb so stairs and gentle ramps stay walkable while steep terrain is excluded.
Raise Resolution and Bounds Size until the navmesh follows the geometry closely enough, watching Polygon Count and Vertex Count as a sanity check.
Add a Pathfind node with the same NavMesh Name to query routes across the mesh.
See also
Pathfind · Physics World · Rigid Body Sim · Geometry (meshes)