Pathfinding AI Won't Move Anywhere

Help and Feedback Scripting Support
#1

I had someone help me remake my pathfinding module, since it was very buggy. The new version of the module somewhat works, which just fixed most of the player chasing stuff, but not so much of the waypoints. I don’t blame them for giving up on this since pathfinding is just so difficult for no reason.

I don’t really know how to describe it and I don’t know if I’m describing it correctly, but the AI will not move to it’s waypoints. It’ll move, but it will just move around in the same spot constantly, as if it was going to a waypoint, and then switching which one it wanted to go to instantly.

https://gyazo.com/a256103dc8e721dc2f0afb62da831cc5

I’ve tried a few things but I can’t really seem to fix the issue, there aren’t any errors either. The AI works fine when its chasing a player.

function followPath(killer, destination)
	local destinationPosition = destination

	if typeof(destination) ~= "Vector3" then
		destinationPosition = destination.Position
	end

	local path = getPath(killer, destinationPosition)

	if path.Status == Enum.PathStatus.Success then -- Successfully generated path to destination
		local waypoints = path:GetWaypoints()

		---- Detect if path becomes blocked
		--blockedConnection = path.Blocked:Connect(function(blockedWaypointIndex)
		--	-- Check if the obstacle is further down the path
		--	--if blockedWaypointIndex >= nextWaypointIndex then
		--		-- Stop detecting path blockage until path is re-computed
		--		blockedConnection:Disconnect()
		--		-- Call function to re-compute new path
		--		followPath(killer, destination)
		--	--end
		--end)

		for i, waypoint in pairs(waypoints) do
			if i == 1 then continue end -- Prevent jitteriness when switching from pursuit to pathfinding

			------------------------------------------
			local part = Instance.new("Part")
			part.Position = waypoint.Position
			part.Size = Vector3.new(0.5, 0.5, 0.5)
			part.Color = Color3.new(1, 0, 1)
			part.Anchored = true
			part.CanCollide = false
			part.CanQuery = false
			part.Parent = workspace
			-------------------------------------------

			killer.Humanoid.WalkSpeed = killer:GetAttribute("WalkSpeed")
			killer.Humanoid:MoveTo(waypoint.Position)-- - target.HumanoidRootPart.CFrame.LookVector * 3)

			--print(waypoint.Action)

			while true do
				if theTarget == nil then
					print("Target is nil")
				end
				if killer.HumanoidRootPart.Position.Y + 1 < destinationPosition.Y then
					killer.Humanoid.Jump = true
					--if destinationPosition.Y - killer.HumanoidRootPart.Position.Y < killer.Humanoid.JumpHeight then
					--end
				end

				if moveToFinishedDone == true or checkForLineOfSight(killer.HumanoidRootPart.Position, destinationPosition) == true then
					moveToFinishedDone = false
					break
				end

				task.wait()
			end
		end
	end
end
1 Like
#2

I believe your NPC is attempting to go to EVERY waypoint at once instead of waiting to get to the one it has to.
I think if you include this line of code after the moveTo command it’ll wait until it gets to its current waypoint and move onto the next.

killer.Humanoid:MoveTo(waypoint.Position)
#3

As @nekstoer said, the AI is probably trying to go to every waypoint. Though it appears he gave you the wrong code :d. To make it wait you’d do Humanoid.MoveToFinished:Wait(). While I can see that you have this in your code.

if moveToFinishedDone == true or checkForLineOfSight(killer.HumanoidRootPart.Position, destinationPosition) == true then
	moveToFinishedDone = false
	break
end

I can’t tell what the values for those are so ill just assume they dont run…
Also why is there a loop? There doesn’t seem to be a reason for the loop.

Code Review :P

First, Im pretty youre making this in a regular script, so I’d suggest you convert that code into a module script so you can make other NPC’s have AI. Unless it’s just 1 AI in the game then it’s fine I guess.

Second, I can see you commented out a chunk of the code. To make a multi-line comment you do the comemnt line followed by 2 square brackets (–[[ ]] ), anything in between the brackets will be a comment.

--[[
this is a comment
this is also a comment
comment 3
]]

.
Thirdly, I would not do this

if killer.HumanoidRootPart.Position.Y + 1 < destinationPosition.Y then
	killer.Humanoid.Jump = true
end

because if there was a small wall you that the AI decided to jump over instead of walk around, the AI would get stuck. And trust me, it is NOT worth the time to code it so it decides to walk off the edge instead of jump off (assuming that’s why the code is there). I’d just leave it as

if waypoint[i].Action == Enum.PathWaypointAction.Jump then
	killer.Humanoid.Jump = true
end

.
Fourthly, instead of making the part in the loop, I’d set it up outside the function and clone the part into the position.
So instead of this being in the loop:

local part = Instance.new("Part")
part.Position = waypoint.Position
part.Size = Vector3.new(0.5, 0.5, 0.5)
part.Color = Color3.new(1, 0, 1)
part.Anchored = true
part.CanCollide = false
part.CanQuery = false
part.Parent = workspace

Put this outside the function:

local pathPoint = Instance.new("Part")
part.Size = Vector3.new(0.5, 0.5, 0.5)
part.Color = Color3.new(1, 0, 1)
part.Anchored = true
part.CanCollide = false
part.CanQuery = false

and replace the old code with this

local newPoint = pathPoint:Clone()
newPoint.Position = waypoint.Position
newPoint.Parent = workspace

This makes your code run faster I guess.
.
Fifthly, you don’t need to use ipairs() anymore in loops you can just put the table as is.
Instead of this:

for i, waypoint in pairs(waypoints) do

you can do this

for i, waypoint in waypoints do
2 Likes
#4

Agh! You’re right, wrong line of code!!! My bad

#5

Hey, so I’ve updated the function to some of the stuff you suggested. I’m gonna remove the whole debugging stuff later because I don’t feel like changing that right now lol, but anyway, I changed the function up a bit and the issue is still occurring, I’ve removed the loop and I’ve added the Humanoid.MoveToFinished:Wait(), and the same issue is still occurring, am I doing it wrong?

function followPath(killer, destination)
	local destinationPosition = destination

	if typeof(destination) ~= "Vector3" then
		destinationPosition = destination.Position
	end

	local path = getPath(killer, destinationPosition)

	if path.Status == Enum.PathStatus.Success then -- Successfully generated path to destination
		local waypoints = path:GetWaypoints()

		for i, waypoint in pairs(waypoints) do
			if i == 1 then continue end -- Prevent jitteriness when switching from pursuit to pathfinding

			------------------------------------------
			local part = Instance.new("Part")
			part.Position = waypoint.Position
			part.Size = Vector3.new(0.5, 0.5, 0.5)
			part.Color = Color3.new(1, 0, 1)
			part.Anchored = true
			part.CanCollide = false
			part.CanQuery = false
			part.Parent = workspace
			-------------------------------------------

			killer.Humanoid.WalkSpeed = killer:GetAttribute("WalkSpeed")
			killer.Humanoid:MoveTo(waypoint.Position)
			killer.Humanoid.MoveToFinished:Wait() -- Wait until the killer reaches the waypoint

			if theTarget == nil then
				print("Target is nil")
				break
			end

			if waypoint[i].Action == Enum.PathWaypointAction.Jump then
				killer.Humanoid.Jump = true
			end

			if checkForLineOfSight(killer.HumanoidRootPart.Position, destinationPosition) then
				break
			end
		end
	end
end
#6

This seems fine, the problem is probably how you are using this function, or something wrong with the checkForLineOfSight / getPath function.

1 Like
#7

I don’t like repeating what other people have already said but anyways, like @grewsxb4 said, the problem is probably caused outside the function.

I don’t think its coming from checkForLineOfSight() or getPath() (would still be nice to those though) but from the code that’s running the followPath(), so if you can, showing us the script thats running the followPath() would be nice.

Code Review V2

you should place this:

if waypoint[i].Action == Enum.PathWaypointAction.Jump then
	killer.Humanoid.Jump = true
end

above killer.Humanoid.MoveToFinished:Wait() since the NPC won’t actually jump as it’s waiting to reach the waypoint then jump.

Also sometimes the NPC will get stuck somewhere somehow, and thus, would make you wait forever when you do killer.Humanoid.MoveToFinished:Wait() so Roblox added an 8 second wait time to combat this. Basically when you do MoveToFinished:Wait() it will either return

  • true if the character has reached the waypoint, or
  • false if 8 seconds has passed and it still hasn’t reached the waypoint.

Allowing you to well, debug it I guess. You can compute another path or just make it stop entirely, really depends on what you want to do with it.

So I’d replace this: killer.Humanoid.MoveToFinished:Wait()
with this:

if not killer.Humanoid.MoveToFinished:Wait() then
	print("NPC couldn't reach waypoint")
	--Compute a new path
end

Also, I appreciate you going over and fixing your code because as it can take quite long time to write them if they’re long (like the first one .-.).

1 Like
#8

The walkTo() function does, this is what it looks like.

-- Pursuing the target
local function walkTo(killer, target, destination, maxDistance)
	killer.Humanoid.WalkSpeed = killer:GetAttribute("SprintSpeed")

	if target then
		local originPos = killer.HumanoidRootPart.Position
		local lineOfSightCheck = checkForLineOfSight(killer.HumanoidRootPart.Position, destination.Position)
		print(lineOfSightCheck)

		if lineOfSightCheck then
			if killer:GetAttribute("HasVoice") then
				local voiceSound = killer.Head:FindFirstChild("Voice")
				if voiceSound and not voiceSound.IsPlaying then
					voiceSound:Play()
				end
			end

			-- Pursue the player directly
			--killer.Humanoid:MoveTo(target.HumanoidRootPart.Position - target.HumanoidRootPart.CFrame.LookVector * 10)
		else 
			-- Engage pathfinding if no direct sight
			followPath(killer, destination)
		end
	else 
		-- Move to the destination if no target
		killer.Humanoid:MoveTo(destination.Position)
	end
end

Also, I have another function that has to do with waypoints, and it’s my patrol() function, I’m not sure if this is the main reason why, but I apologize for not showing this sooner.

function patrol(killer)
	local waypoints = workspace.Map:WaitForChild("Waypoints"):GetChildren()
	local randomWaypoint = math.random(1, #waypoints)

	walkTo(killer, nil, waypoints[randomWaypoint], killer:GetAttribute("MaxDistance"))
	--killer.Humanoid.MoveToFinished:Wait()

	--while true do
	--	if moveToFinishedDone == true or checkForLineOfSight(killer.HumanoidRootPart.Position, waypoints[randomWaypoint].Position) == true then
	--		moveToFinishedDone = false
	--		break
	--	end

	--	task.wait()
	--end
end
#9

The above functions don’t seem to be wrong either.
I believe there’s a loop somewhere in your code thats calling the functions without pausing it, leading to the jitteriness. I could be wrong. But only way to know is if you show more of the script.

#10

I could send you the full module in private messages if you’d like.

#11

I dont think the module script is the problem but the script thats calling and using the module script

#12 
local ServerScriptService = game:GetService("ServerScriptService")
local ModulesFolder = ServerScriptService:WaitForChild("Modules")
local KillerAIFolder = ModulesFolder:WaitForChild("KillerAIs")

local AI = require(KillerAIFolder:WaitForChild("Default"))

local killer = script.Parent
AI.start(killer)
#13

Oh… Didn’t expect the entire code to be written in the Module. I guess, you can send the module to me in private messages.