NPC Immediately stops moving when another one spawns

[imnotaguest1121 (Diabolical_Subspace)]

Heya there.

I’m rewriting an OOP NPC System. There’s however an issue with the system. The issue being that whenever a new NPC spawns in when one NPC is in the workspace, the first NPC immediately stops all movement.

--[[SERVICES]]--
local Players = game:GetService("Players")
local PathfindingService = game:GetService("PathfindingService")

--[[NPC MODEL FOLDERS]]--
local NPCFolder = game:GetService("ServerScriptService").NPCS
local NoobsFolder = NPCFolder.Noobs

--[[MODULE]]--
local BaseNPCModule = {}
BaseNPCModule.__index = BaseNPCModule

function BaseNPCModule:CreateNPC(UnitName, UnitTeam, Weapon, Special)
	--//Checking to see if the unit exists.
	for _, FindUnit in pairs(NoobsFolder:GetChildren()) do
		if FindUnit:IsA("Model") and FindUnit.Name == UnitName then

			--//Creating the unit.
			self.Unit = FindUnit:Clone()
			self.Humanoid = self.Unit:FindFirstChildWhichIsA("Humanoid")
			self.Unit.Parent = game.Workspace
			self.UnitTeam = game:GetService("CollectionService"):AddTag(self.Unit, UnitTeam)
			self.Is_Special = Special

			--//Giving it functionality
			if not self.Is_Special then
				--//Assuming it's just a basic NPC (E.g. Noob/Zombie Sworder)
				--//Otherwise, the NPC is going to inheritate only the FindNearestTargets and Pathfind functions.
				task.spawn(function()
					while task.wait(0.05) do
						task.spawn(function()
							local Target = BaseNPCModule:FindNearestTargets()

							if Target then
								BaseNPCModule:Pathfind(Target)
							end
						end)
					end
				end)
				
			end
		end
	end
end

function BaseNPCModule:FindNearestTargets()
	local Targets = {}
	local Nearest = math.huge
	local Target = nil

	for _, PossibleTargets in ipairs(workspace:GetChildren()) do
		if PossibleTargets:IsA("Model") and PossibleTargets:FindFirstChildWhichIsA("Humanoid") then
			local Humanoid = PossibleTargets:FindFirstChildWhichIsA("Humanoid")
			if Humanoid.Health <= 1 then
				--//They're dead.
				return
			end

			--//If they aren't dead, check the distance.
			local Distance = (PossibleTargets.PrimaryPart.Position - self.Unit.PrimaryPart.Position).Magnitude
			if Distance <= Nearest then

				if PossibleTargets:HasTag("Zombies") and self.Unit:HasTag("Noobs") then
					table.insert(Targets,{
						Magnitude = Nearest,
						FoundTarget = PossibleTargets
					})
				elseif PossibleTargets:HasTag("Noobs") and self.Unit:HasTag("Zombies") then
					table.insert(Targets,{
						Magnitude = Nearest,
						FoundTarget = PossibleTargets
					})
				end

			end
		end
	end
	
	for _, Entry in pairs(Targets) do
		local magnitude = Entry.Magnitude
		local target = Entry.FoundTarget
		
		if magnitude <= Nearest then
			Nearest = magnitude
			Target = target
		end
	end

	return Target
end

function BaseNPCModule:Pathfind(Target)
	local NewPath = PathfindingService:CreatePath({
		AgentRadius = 3,
		AgentHeight = 5,
		AgentCanJump = true,
	})
	
	NewPath:ComputeAsync(self.Unit.PrimaryPart.Position, Target.PrimaryPart.Position)
	if NewPath.Status == Enum.PathStatus.Success then
		local Waypoints = NewPath:GetWaypoints()

		for i, Waypoint in ipairs(Waypoints) do
			if i <= 2 then continue end
			if Waypoints[4] then
				self.Humanoid:MoveTo(Waypoints[4].Position)

				local TimeOut = self.Humanoid.MoveToFinished:Wait()
				if not TimeOut then
					warn("NPC got stuck... Recalculating!")
					BaseNPCModule:Pathfind(Target)
				end
			end
		end
	end
end

return BaseNPCModule

[Kitsomia (Mia)]

When you create an NPC, you’re not creating a new object profile for the new npc you’re creating.

function BaseNPCModule:CreateNPC(UnitName, UnitTeam, Weapon, Special)
	--//Checking to see if the unit exists.
	for _, FindUnit in pairs(NoobsFolder:GetChildren()) do
		if FindUnit:IsA("Model") and FindUnit.Name == UnitName then

			--// Creating the unit.
			-- // Still using the meta methods table as it's obj profile
			-- // So you're just replacing the last NPC you just created with this new one
			self.Unit = FindUnit:Clone()

Vs

function BaseNPCModule:CreateNPC(UnitName, UnitTeam, Weapon, Special)
	--// Checking to see if the unit exists.
	local unit = NoobsFolder:FindFirstChild(UnitName)
	if not unit then return end
	local self = setmetatable({}, BaseNPCModule) -- // The obj/profile
	--//Creating the unit.
	self.Unit = unit:Clone()
	-- ...
	return self

[imnotaguest1121 (Diabolical_Subspace)]

Sorry for the late response, but I’ve tried implementing your solution to the code, now it keeps saying Attempt to index nil with "PrimaryPart" on the FindNearestTarget code.

[Kitsomia (Mia)]

For any direct calls you have like BaseNPCModule:FindNearestTargets(), BaseNPCModule:Pathfind(Target) and BaseNPCModule:Pathfind(Target), should replace BaseNPCModule with self.

If you’re making a methods table that’s for a class, typically you’d want to use self:foo(...) over methods:foo(...) even within the function declared.

function methods:Foo(a, b, c): any
	if not self.Target then
		self:Chase(self.Target)

---
obj:Foo()
--- // and not
methods:Foo()
-- // Unless you want to do
methods.foo(obj, a, b, c)

I recommend doing methods.foo(obj, a, b, c) on objs that you might have cleaned up before a process is finished. Otherwise use that method similar to how you’d do compositional programming.