Trending Society: A curated library for people building with 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.

--- name: roblox-npc-ai description: "Use when creating or fixing Roblox NPCs, bots or enemies: pathfinding, state machines, line of sight, spawns, AI update loops." when_to_use: "Also when NPCs get stuck, walk through walls, chase wrongly, lag the server, or bots need to fill empty servers." last_reviewed: 2026-10-14 sources: - https://raw.githubusercontent.com/Roblox/creator-docs/main/content/en-us/characters/pathfinding.md - https://create.roblox.com/docs/projects/server-authority - original --- # 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 ```luau 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) 1. **Distance** `(a-b).Magnitude`: cheapest, always first 2. **FOV** `forward:Dot(toTarget)` cosine; use a configured cone for your game, not a universal angle 3. **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`.

Roblox Npc AI