Troubleshooting

Problems in the order people actually hit them. Start with the Quick Triage table: it resolves most issues in under a minute.

Quick triage

The two diagnostics that answer almost everything

1. Turn on Draw Debug Volumes (navigation manager → 6. Debug).

This draws the octree. It tells you what the pathfinder actually sees, which is frequently not what you assume:

• No small voxels around a doorway → the pathfinder can't route through it either.
• No voxels at all in a region → it's outside World Extent, or the chunk hasn't generated.
• Solid voxels where there's visibly open air → Clearance Padding is too large.

2. Check the Output Log (Window → Output Log) and filter for Lcm. The plugin logs the specific reason a query failed.

1. Nothing moves

Work in this order.

Is there a navigation manager?

Output Log shows LCMBTTask_FlyTo: No SVO Manager found in the level! → drag an LcmNavigationManagerSVO into the level. One per level, required.

Did the AI possess the pawn?

• Pawn → Class Defaults → Auto Possess AI = Placed in World or Spawned
• Pawn → Class Defaults → AI Controller Class is set
• The controller actually runs the tree (Run Behavior Tree, or a StateTreeAIComponent with a State Tree assigned)

Can the pawn move at all?

It needs a movement component that supports flight. Floating Pawn Movement is the simple choice. Check its Max Speed isn't 0.

Is the goal set?

Print the blackboard key (or StateTree parameter). A goal of (0,0,0) means it was never set, or was set after the tree started.

2. Agent moves, but badly

3. "No path found"

First: is the goal reachable at all?

• Inside the navigation volume? Outside World Extent there is no data. Enlarge it, or move the goal in.
• Inside geometry? A goal (or start) buried in a wall has no free voxel. Move it into open air.
• Genuinely enclosed? If the destination is sealed off, failure is correct.

The classic: padding sealed the opening

This is the most common cause of a mystifying "no path".

If Clearance Padding is close to Min Voxel Size, obstacle inflation fills narrow openings completely. A 2 m doorway with 100 cm voxels and 100 cm padding can vanish entirely.

Fix: lower Clearance Padding, or lower Min Voxel Size so the opening survives the inflation. Confirm with Draw Debug Volumes: you should see free voxels through the opening.

Short paths work, long ones fail

Almost always an infinite world issue: the route crosses chunks that haven't generated yet.

• Turn on Persistent Skeleton under 5. Coarse Skeleton (optional). It is off by default
• it is what allows long-range planning before the detail exists, and it is the first thing to try when an agent loses routability over ground it has already crossed.
• For routing to be complete on the very first frame, including into space the agent has never visited, tick Use Baked Skeleton (also under 5. Coarse Skeleton (optional)) and then click the Bake Skeleton button, which appears in the banner once that option is on.
• Tick Assist Infinite Streaming on the Fly To task for agents that must traverse the frontier.
• Leave Chunk Size at 8000 unless you have a specific reason and will re-test long routes.

Everything fails immediately

The volume never built. Check Auto Build On Play is on, or that you call BuildSVO. With Draw Debug Volumes on, you should see the octree at BeginPlay.

4. Agents ignore geometry

If agents fly through a wall, the wall isn't in the octree.

1. Does the mesh have collision? Voxelization uses collision, not visual geometry. No Collision = invisible to navigation.
2. Is its channel in Obstacle Query Channels? (3. Collision)
3. Is Allowed Obstacle Classes filtering it out? Empty = allow everything, which is what you normally want.
4. Was it added after the build? Static geometry is baked at build time. Something spawned later needs either a rebuild or a Dynamic Obstacle component.
5. Is it too thin? Geometry thinner than a voxel can be missed. Lower Min Voxel Size, or thicken the collision.

5. Dynamic obstacles do nothing

1. Does the actor have an LCM Nav3D Dynamic Obstacle component? Moving an actor without one changes nothing as far as navigation is concerned, and produces no error.
2. Does its mesh have collision enabled?
3. Is Update Distance Threshold too high? It won't restamp until the actor moves that far (default 50 cm).
4. Reaction too slow? Lower Finite Obstacle Update Interval (default 0.1 s).
5. Using Tracked Components? If the list is non-empty, only those components are tracked, so make sure the blocking one is in it.

See Tutorial 05.

6. Performance

Build is slow / hitches when streaming

• Raise Min Voxel Size (the biggest lever by far).
• Keep Use GPU Voxelization on.
• Lower Max Generations Per Frame to spread work (world fills in more slowly, but smoothly).

Frame rate drops with many agents

• Lower Max Path Requests Per Frame to cap per-frame planning.
• Use cheaper avoidance: Reactive rather than Predictive.
• For agents sharing a goal, enable Use Flow Fields.
• Past a few hundred agents, move to Mass Entity. Actor ticks, not pathfinding, are the ceiling.

Memory too high

• Raise Min Voxel Size (memory scales steeply with resolution).
• Shrink World Extent to just your play space.
• In infinite worlds, keep Chunk Size at the default.

Debug drawing is itself slow

Expected: it's a debug tool. Raise Debug Redraw Coalesce Seconds, or turn it off.

7. Editor and install

8. Determinism and multiplayer

If you need identical results across runs (replays, lockstep, automated tests):

• Turn Use GPU Voxelization off.

Path solving already runs on the CPU and is deterministic by design. Voxelization is the part that can vary: GPU execution order isn't guaranteed run-to-run, so force the CPU voxelizer when you need a bit-identical rebuild.

Still stuck?

Gather these before asking for help, since they identify most problems immediately:

1. Draw Debug Volumes screenshot of the area that misbehaves.
2. Output Log filtered to Lcm.
3. Manager settings: Infinite World, World Extent/Chunk Size, Min Voxel Size, Clearance Padding.
4. Which path you're using: Behavior Tree, StateTree, or Mass.
5. Does the equivalent demo map work? If yes it's a setup issue in your level; if no it's an install issue.

Then bring them to the community Discord: https://discord.gg/nXkpD6uaBG

Open a Technical Support ticket in #get-help and you get a private channel with the author. First reply within 24 hours on weekdays. #support-faq there carries this same triage list, and #known-issues tracks confirmed defects with their workarounds - worth checking before you write.