Fix Godot NavigationAgent Stuck on Obstacles

Godot 4’s navigation system pairs a pathfinder on a baked mesh with an RVO (reciprocal velocity obstacle) avoidance step that steers the agent away from other agents and obstacles. Either half can fail independently. If your enemy stops a meter short of the player and shakes in place, the pathfinder has delivered a good path but the avoidance module is outputting a zero velocity because the scene is too crowded.

Check the agent radius against the passage width

The single setting that causes the most stuck-agent reports is radius. RVO refuses to emit a velocity that would bring the agent’s radius circle into contact with any obstacle or other agent. If the gap between two walls is 1.0 meter and your radius is 0.6, the clearance on each side is 0.4 — less than the radius — so RVO picks zero velocity as the safest choice.

var agent: NavigationAgent3D = $NavigationAgent3D
agent.radius = 0.35   # smaller than half the narrowest doorway
agent.height = 1.8
agent.max_speed = 4.0

Agent radius and navmesh agent radius are separate. The baked mesh is inset by whatever agent radius you used at bake time. The RVO radius is runtime only. Keep the RVO radius equal to or slightly smaller than the baked radius so the agent never wants to go where the mesh has no room.

Set path_desired_distance correctly

Every frame the agent looks at the next waypoint in its path and asks “am I close enough to move on?” That check uses path_desired_distance. If this value is smaller than one frame’s worth of movement at your max speed, the agent overshoots the waypoint, turns around, overshoots again, and never advances. A safe rule is:

agent.path_desired_distance = max(0.5, agent.max_speed * get_physics_process_delta_time() * 2.0)
agent.target_desired_distance = 1.0

target_desired_distance controls when the agent considers the final destination reached. Setting it to match your melee range or interaction radius stops enemies from trying to stand exactly on the player’s feet.

Decide which obstacles carve vs avoid

Godot distinguishes two obstacle behaviors. A NavigationObstacle with affect_navigation_mesh on is a carver: it modifies the baked mesh and forces the pathfinder to route around it. This costs a rebake whenever the obstacle moves. Without that flag, the obstacle is RVO-only — invisible to the pathfinder, visible to the avoidance step. Use carving for static or rarely-moving props (a closed door, a parked cart) and RVO-only for moving hazards (a patrolling enemy, a rolling barrel).

var obstacle: NavigationObstacle3D = $NavigationObstacle3D
obstacle.affect_navigation_mesh = true
obstacle.carve_navigation_mesh = true
obstacle.vertices = [...]

Watch for agent_max_speed throttling

RVO selects the best velocity whose magnitude is at most max_speed. If a script resets max_speed to zero during a stunned state and you forget to restore it, the agent visually freezes and the developer suspects a navigation bug. Log the velocity each frame to rule this out:

func _physics_process(delta):
    var next := agent.get_next_path_position()
    var dir := (next - global_position).normalized()
    agent.set_velocity(dir * agent.max_speed)
    print("vel", agent.max_speed, "next", next)

If next equals your current position, the pathfinder believes you are at the waypoint — back to the desired-distance check. If next is sensible but the agent will not move, confirm you are passing velocity through the velocity_computed signal, not applying the raw direction. In Godot 4 the RVO step returns its final velocity via that signal; the raw direction will fight avoidance.

Trigger targeted rebakes

For dynamic level elements that carve the mesh, call NavigationServer3D.map_force_update sparingly after they move. A full rebake is expensive; prefer to limit carving obstacles to a handful of objects. If you have more than a few dozen moving carvers, you are fighting the architecture — switch them to RVO-only and accept some path re-evaluation.

“Stuck agents are a physics problem masquerading as an AI problem. Tune the radius first and the behavior trees second.”

Related Issues

For related character movement bugs, see Fix Godot characterbody move and slide no movement, and for avoidance-style physics issues, Fix Godot characterbody2d jittering sliding walls.

Tip: enable “Show Navigation” in the debug menu and watch the computed velocity arrow — if it points at zero, RVO is why.