Roblox NPC & AI
When to Load
Load for NPCs/enemies: pathfinding, state machines, LOS/FOV detection, spawns, AI loops, or physics ownership.
Quick Reference
PathfindingService
local path = PathfindingService:CreatePath({
AgentRadius = 2, AgentHeight = 5, AgentCanJump = true,
Costs = { Water = 20, DangerZone = math.huge },
})
path:ComputeAsync(npcPos, targetPos)
if path.Status ~= Enum.PathStatus.Success then return end
for _, wp in path:GetWaypoints() do
if wp.Action == Enum.PathWaypointAction.Jump then humanoid.Jump = true end
humanoid:MoveTo(wp.Position)
if not humanoid.MoveToFinished:Wait() then return end
end
- Recompute on blocked with a bounded retry or cancellation policy.
- In Studio, test
Workspace.PathfindingUseImprovedSearch on representative maps before rollout; it is not scriptable.
- Avoid long requests and repeated recomputation. Moving collidable geometry can trigger navigation-mesh work.
- Region modifiers: anchored part +
PathfindingModifier Label → Costs
PassThrough = true for doors; PathfindingLink for disconnected navmesh
math.huge cost = non-traversable
State Machine
idle → patrol → chase → attack → flee → dead
- idle/patrol → chase (player detected) → attack (in range) → idle (lost)
- any → flee (health low) → idle (safe); any → dead (health ≤ 0)
- Transitions own movement changes, target cleanup, and cancellation
Detection (distance → FOV → LOS)
- Distance
(a-b).Magnitude: cheapest, always first
- FOV
forward:Dot(toTarget) cosine; use a configured cone for your game, not a universal angle
- LOS
workspace:Raycast: expensive, last
- If the design includes hearing or proximity detection, make it a separate configured signal rather than a universal FOV bypass.
Network Ownership
- Classic projects may use
SetNetworkOwner(nil) for physics-sensitive NPCs, but it is not complete security. In Server Authority projects, configure the authority model instead of treating network ownership as the security boundary.
Update Loop
- Throttle and stagger AI based on NPC count, path cost, and profiler evidence, not a universal tick rate. Keep NPC decisions and movement server-side; client code may handle presentation.
For spawners, lifecycle cleanup, timeout handling, and performance budgets, load references/full.md.
1---2name: roblox-npc-ai3description: Use when creating Roblox NPCs or enemies with pathfinding, state machines, line-of-sight or FOV detection, spawns, or AI update loops.4---56# Roblox NPC & AI78## When to Load910Load for NPCs/enemies: pathfinding, state machines, LOS/FOV detection, spawns, AI loops, or physics ownership.1112## Quick Reference1314### PathfindingService1516```luau17local path = PathfindingService:CreatePath({18 AgentRadius = 2, AgentHeight = 5, AgentCanJump = true,19 Costs = { Water = 20, DangerZone = math.huge },20})21path:ComputeAsync(npcPos, targetPos)22if path.Status ~= Enum.PathStatus.Success then return end23for _, wp in path:GetWaypoints() do24 if wp.Action == Enum.PathWaypointAction.Jump then humanoid.Jump = true end25 humanoid:MoveTo(wp.Position)26 if not humanoid.MoveToFinished:Wait() then return end27end28```2930- Recompute on blocked with a bounded retry or cancellation policy.31- In Studio, test `Workspace.PathfindingUseImprovedSearch` on representative maps before rollout; it is not scriptable.32- Avoid long requests and repeated recomputation. Moving collidable geometry can trigger navigation-mesh work.33- Region modifiers: anchored part + `PathfindingModifier` Label → Costs34- `PassThrough = true` for doors; `PathfindingLink` for disconnected navmesh35- `math.huge` cost = non-traversable3637### State Machine3839`idle → patrol → chase → attack → flee → dead`40- idle/patrol → chase (player detected) → attack (in range) → idle (lost)41- any → flee (health low) → idle (safe); any → dead (health ≤ 0)42- Transitions own movement changes, target cleanup, and cancellation4344### Detection (distance → FOV → LOS)45461. **Distance** `(a-b).Magnitude`: cheapest, always first472. **FOV** `forward:Dot(toTarget)` cosine; use a configured cone for your game, not a universal angle483. **LOS** `workspace:Raycast`: expensive, last49- If the design includes hearing or proximity detection, make it a separate configured signal rather than a universal FOV bypass.5051### Network Ownership52- Classic projects may use `SetNetworkOwner(nil)` for physics-sensitive NPCs, but it is not complete security. In Server Authority projects, configure the authority model instead of treating network ownership as the security boundary.5354### Update Loop5556- Throttle and stagger AI based on NPC count, path cost, and profiler evidence, not a universal tick rate. Keep NPC decisions and movement server-side; client code may handle presentation.5758For spawners, lifecycle cleanup, timeout handling, and performance budgets, load `references/full.md`.