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Troubleshooting

Common issues and their fixes. Most map back to one of the rules in Tuning.

tip

If you see the drone stuck, try disabling the collision temporarily, or reduce the size of the collision sphere.

"Path Not Found" every time​

Cause: the pawn's collision blocks the navigation trace channel, so every query self-hits. The included BP_AIDrone is already transparent, so this usually only happens on a custom pawn. Fix: make the custom pawn transparent to the channel — see Drone Collision Setup.

"Path Not Found" only sometimes / near edges​

Cause: the start or goal is outside any nav volume, or further than MaxSearchDistance from the nearest node, so it can't snap onto the graph. Fix: extend a BP_DroneNavVolume to cover that airspace and re-bake. Use DrawNearestNodeSearch? to see where the snap is searching.

The drone clips wall corners​

Cause: clearance is set to roughly the agent radius with no margin; path smoothing pulls the route tight to that boundary at corners. Fix: raise TraceRadius and NodeClearanceRadius to agent radius + ~25–30 (e.g. ~105 for a ~75 drone), keep them equal, and re-bake. See Tuning → Clearance.

Lots of red (isolated) nodes / the path routes oddly​

Cause: a fragmented graph — usually clearance set so high that corridors get pruned, or volumes that don't quite reach each other. (Connection distance can no longer be too small — it's derived from GridSpacing and auto-clamped to the √3 floor.) Fix: lower NodeClearanceRadius/TraceRadius if corridors are over-pruned; make sure adjacent volumes overlap or abut so their nodes are within linking range. Heed the bake-time isolated-node warning and confirm with Show Nav Graph.

Bake fails with "Runaway loop detected"​

Cause: the connection build ran past Blueprint's single-frame safety limit (~1,000,000 iterations) before finishing, so the bake aborts and leaves the graph partly connected. You'll only hit this at extremes — a very large volume set to a very fine GridSpacing, which produces a huge, tightly-packed node cloud in one region. The bake also prints a warning up front when it estimates the build will get close to this limit, so watch the log. Fix (1) — raise the limit: this safety limit is configurable. Go to Project Settings → Engine → General Settings, find Maximum Loop Iteration Count (or just type "Maximum Loop Iteration Count" into the Project Settings search box), and raise it from the default 1,000,000 to e.g. 10,000,000 or higher, then re-bake. If the bake log shows the runaway message, this is usually the quickest fix. Fix (2) — reduce the node count: alternatively, give that region a coarser GridSpacing (fewer nodes), or split one oversized volume into a few smaller volumes that cover only the airspace you actually need, then re-bake. Mixing a coarse volume over open space with a fine one over the cluttered area is the intended pattern — see Tuning → Set density per volume.

Output log showing the "Runaway loop detected" warning during a bake

The path goes through a wall​

Cause: the baked graph doesn't know about that wall — it was added/moved after the last bake, or it isn't solid to the trace channel in the editor (e.g. a dynamically-revealed object). Fix: make sure the wall has collision on the nav channel in-editor, then re-bake. Verify with Show Nav Graph that no links cross it.

The drone wedges against a wall​

Cause: AcceptanceRadius is smaller than the drone's body, so the planner threads it through a gap narrower than it is. Fix: set AcceptanceRadius to roughly the drone's bounds (~100).

Patrol won't start / drone ignores the path​

Cause: marker spline positions weren't computed, or the PatrolPath reference isn't set. Fix: confirm the BP_AIDrone's PatrolPath is assigned, SnapMarkersInEditor? is on, and the Markers array has no empty entries. Nudge any property on the path to re-run its Construction Script. See Patrol.

Changes to a volume's settings don't take effect​

Cause: the graph is baked — it reflects the last bake, not your live edits. Fix: after changing a volume's GridSpacing (or any geometry/clearance), re-bake from the BakeDroneNav widget.

A scaled volume's nodes look too sparse / oddly spaced​

Cause: the volume actor has a non-uniform scale. Density derives from one scale axis, so non-uniform scale skews spacing. Fix: keep volume scale roughly uniform, or (better) reset scale to 1 and resize via the box Extent instead.

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