How to make an enemy AI wander randomly and stay within a zone?

Help and Feedback Scripting Support
#1

So I need my enemy NPCs to be able to wander freely within a specific zone. Along with this, if they are chasing a player and the player leaves the zone, they should not follow them outside the zone. I have a cylinder part stretched over the zone they can stay in but I don’t know how to implement this aspect into my code. (I got this script from a tutorial since I’m not very familiar with AI or pathfinding)

local myHuman = script.Parent:WaitForChild("Humanoid")
local myRoot = script.Parent:WaitForChild("HumanoidRootPart")
local head = script.Parent:WaitForChild("Head")
local lowerTorso = script.Parent:WaitForChild("Torso")

local grab = script.Parent:WaitForChild("Grab")
local grabAnim = myHuman:LoadAnimation(grab)
local walk = script.Parent.Humanoid.walkani
local walkAnim = myHuman:LoadAnimation(walk)
grabAnim.Priority = Enum.AnimationPriority.Action

local damageAmt = 10

--local grabSound = head:WaitForChild("Attack")

local clone = script.Parent:Clone()

function walkRandomly()
	local xRand = math.random(-25,25)
	local zRand = math.random(-25,25)
	local goal = myRoot.Position + Vector3.new(xRand,0,zRand)

	local path = game:GetService("PathfindingService"):CreatePath()
	path:ComputeAsync(myRoot.Position, goal)
	local waypoints = path:GetWaypoints()

	if path.Status == Enum.PathStatus.Success then
		for _, waypoint in ipairs(waypoints) do
			if waypoint.Action == Enum.PathWaypointAction.Jump then
				myHuman.Jump = true
			end
			myHuman:MoveTo(waypoint.Position)
			local timeOut = myHuman.MoveToFinished:Wait(1)
			if not timeOut then
				print("Got stuck")
				myHuman.Jump = true
				walkRandomly()
			end
		end
	else
		print("Path failed")
		wait(1)
		walkRandomly()
	end
end

function findPath(target)
	local path = game:GetService("PathfindingService"):CreatePath()
	path:ComputeAsync(myRoot.Position,target.Position)
	local waypoints = path:GetWaypoints()

	if path.Status == Enum.PathStatus.Success then
		for _, waypoint in ipairs(waypoints) do
			if waypoint.Action == Enum.PathWaypointAction.Jump then
				myHuman.Jump = true
			end
			myHuman:MoveTo(waypoint.Position)
			local timeOut = myHuman.MoveToFinished:Wait(1)
			if not timeOut then
				myHuman.Jump = true
				print("Path too long!")
				findPath(target)
				break
			end
			if checkSight(target) then
				repeat
					print("Moving directly to the target")
					myHuman:MoveTo(target.Position)
					attack(target)
					wait(0.1)
					if target == nil then
						break
					elseif target.Parent == nil then
						break
					end
				until checkSight(target) == false or myHuman.Health < 1 or target.Parent.Humanoid.Health < 1
				break
			end
			if (myRoot.Position - waypoints[1].Position).magnitude > 20 then
				print("Target has moved, generating new path")
				findPath(target)
				break
			end
		end
	end
end

function checkSight(target)
	local ray = Ray.new(myRoot.Position, (target.Position - myRoot.Position).Unit * 40)
	local hit,position = workspace:FindPartOnRayWithIgnoreList(ray, {script.Parent})
	if hit then
		if hit:IsDescendantOf(target.Parent) and math.abs(hit.Position.Y - myRoot.Position.Y) < 3 then
			print("I can see the target")
			return true
		end
	end
	return false
end

function findTarget()
	local dist = 50
	local target = nil
	local potentialTargets = {}
	local seeTargets = {}
	for i,v in ipairs(workspace:GetChildren()) do
		local human = v:FindFirstChild("Humanoid")
		local torso = v:FindFirstChild("Torso") or v:FindFirstChild("HumanoidRootPart")
		if human and torso and not v:FindFirstChild("AI") then
			if (myRoot.Position - torso.Position).magnitude < dist and human.Health > 0 then
				table.insert(potentialTargets,torso)
			end
		end
	end
	if #potentialTargets > 0 then
		for i,v in ipairs(potentialTargets) do
			if checkSight(v) then
				table.insert(seeTargets, v)
			elseif #seeTargets == 0 and (myRoot.Position - v.Position).magnitude < dist then
				target = v
				dist = (myRoot.Position - v.Position).magnitude
			end
		end
	end
	if #seeTargets > 0 then
		dist = 200
		for i,v in ipairs(seeTargets) do
			if (myRoot.Position - v.Position).magnitude < dist then
				target = v
				dist = (myRoot.Position - v.Position).magnitude
			end
		end
	end
	return target
end

function died()
	wait(5)
	clone.Parent = workspace
	game:GetService("Debris"):AddItem(script.Parent,0.1)
end

myHuman.Died:Connect(died)

lowerTorso.Touched:Connect(function(obj)
	if not obj.Parent:FindFirstChild("Humanoid") then
		myHuman.Jump = true
	end
end)

function attack(target)
	if (myRoot.Position - target.Position).magnitude < 5 then
		--grabSound:Play()
		if target.Parent ~= nil and not target.Parent:FindFirstChild("AI") then
			grabAnim:Play()
			wait(0.3)
			target.Parent.Humanoid:TakeDamage(damageAmt)
		end
		wait(1.25)
	end
end

function main()
	local target = findTarget()
	if target then
		myHuman.WalkSpeed = 14
		findPath(target)
		walkAnim:Play()
	else
		myHuman.WalkSpeed = 9
		walkRandomly()
		walkAnim:Play()
	end
end

while wait(0.1) do
	if myHuman.Health < 1 then
		break
	end
	main()
end

Thank you for your help!

1 Like
#2

Check whether the target location where it should walk towards is not outside your part, you could do it like so

if targetPosition.X < part.Position.X + part.Size.X / 2 and targetPosition.X > part.Position.X - part.Size.X / 2 then
   -- is within the X range of the part
   if targetPosition.Z < part.Position.Z + part.Size.Z / 2 and targetPosition.Z > part.Position.Z - part.Size.Z / 2 then
      -- is within the Z range of the part

   end
end
4 Likes
#3

To expand on what @theworldis_socruel has said, inside of the if parameter you should set your enemies new movement goal to the center of the zone. I also recommend doing the above with y coordinates if dealing with slopes. I would also make your enemies targeting system a coroutine or any other function that can easily be broken so that the enemy doesn’t try to track you after it’s been directed to move back. Hope this helps.

2 Likes
#4

Thank you, although I am not sure where I should insert this check in my script, I’ve tried different areas of my script but none of them have worked correctly. (I am not good with this AI stuff lol)

#5

Right before you let the npc’s move, you should have those two if statements!

1 Like