How to Fix Unreal NavMesh Not Updating for Runtime-Spawned Geometry

AI in your Unreal game walks straight through walls you spawned at runtime because the navmesh never updated. Dynamic navigation generation is off by default in many setups. Here is how to enable runtime rebuilds.

How to fix it

1. Enable dynamic generation

On the RecastNavMesh actor, set Runtime Generation to Dynamic. With it on Static, navigation tiles are baked once and never reflect runtime-spawned obstacles or floors.

2. Make actors affect navigation

Confirm your spawned actors have collision and Can Ever Affect Navigation enabled. An actor with navigation disabled is invisible to the navmesh even when dynamic generation is on.

3. Trigger a rebuild when needed

After large procedural spawns, call UNavigationSystemV1::Build or rely on dirty-area updates so the affected tiles regenerate before agents try to path across them.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every Unreal Engine error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.