Attempt to index nil with 'Position'

[Feugazi]

I am writing a script for a Lightning Tower to target units in a tower defense game. I am currently working on the Lightning attack of the tower.

Here is the script that creates the Lightning:

Summary

local module = {}

function draw(p1, p2, Parent)
	local dist = (p2.Position - p1.Position).Magnitude
	local part = Instance.new("Part", Parent)
	part.CanCollide = false
	part.Anchored = true
	part.Position = p1.Position
	part.Material = "Neon"
	part.BrickColor = BrickColor.new("New Yeller")


	part.Size = Vector3.new(.5,.5,dist)
	part.CFrame = CFrame.new(p1.Position, p2.Position) * CFrame.new(0,0,-dist/2)
end

module.CreateLightning = function(startPosition, endPosition, numberOfPoints)
	
	local model = Instance.new("Model",game.Workspace)
	local points = {}
	
	for i = 0,numberOfPoints do
		
		local offset = Vector3.new(math.random(-5,5),math.random(-2,2),math.random(-5,5))
		
		if i == 0 or i == numberOfPoints then
			offset = Vector3.new(0,0,0)
		end
		
		local part = Instance.new("Part", model)
		part.Anchored = true
		part.CanCollide = false
		part.Size = Vector3.new(.5,.5,.5)
		part.Material = "Neon"
		part.BrickColor = BrickColor.new("New Yeller")
		
		part.Position = startPosition + (endPosition - startPosition).Unit * i * (endPosition - startPosition).Magnitude/numberOfPoints
		
		points[#points+1] = part
		
	end
	
	
	for i = 1,#points do
		if points[i+1] ~= nil then
			draw(points[i], points[i-1], model)
		end
	end
	
	return model
end


return module

Here is the script that runs the Tower:

Summary

local tower = script.Parent.Position
local mobs = workspace.Board.MobRealm
local ball = tower.Parent.Ball
local ServerScriptService = game:GetService("ServerScriptService")
local lightningModule = require(ServerScriptService:WaitForChild("Lightning"))

local function FindNearestTarget()
	local maxDistance = 70
	local nearestTarget = nil


	for i, target in ipairs(mobs:GetChildren()) do	
		local distance = (target.HumanoidRootPart.Position - tower.Position).Magnitude
		if distance < maxDistance then
			nearestTarget = target
			maxDistance = distance
		end
	end
	
	
	return nearestTarget
end


while true do
	
	local target = FindNearestTarget()
	if target then
		
		game.TweenService:Create(ball,TweenInfo.new(2),

			{
				Transparency = 0,
				Color = Color3.fromRGB(255, 170, 0)
			}

		):Play()

		wait(2)
		
		local model = lightningModule.CreateLightning(ball.Position, target.HumanoidRootPart.Position,10)
		game.Debris:AddItem(model,1)
		
		target.Humanoid:TakeDamage(25)
		
		game.TweenService:Create(ball,TweenInfo.new(.5),

			{
				Transparency = .4,
				Color = Color3.fromRGB(255, 0, 0)
			}

		):Play()

		wait(.5)

	end
	
	task.wait(2.5)
	--2.5 between shots

end

Whenever this is ran, I get the error:
ServerScriptService.Lightning:4: attempt to index nil with 'Position' on Lightning Script

I have looked around for a solution but can’t seem to find a fix that works.

The lightning module was from a video, where no errors were present.

[ValiantWind (Val)]

It means that in the Lightning script on line 4, they cannot find the “Position” property, or in other words, the position property does not exist.

[Feugazi]

So this seems to be an issue with the module script as every value for p1 and p2 turn up nil.

I created a script to test the module which is:

local lightningModule = require(game.ServerScriptService.Lightning)

lightningModule.CreateLightning(game.Workspace.Tower.Position, game.Workspace.Target.Position, 10)

The parts for the lightning are created but the same error persists.

I’m still unsure of why it is failing to find a position, as the part are spawned in?

[ValiantWind (Val)]

@Feugazi

lightningModule.CreateLightning(game.Workspace.Tower.Position, game.Workspace.Target.Position, 10)

It’s because you’re calling game.Workspace.Tower.Position and game.Workspace.Target.Position instead of game.Workspace.Tower and game.Workspace.Target

In the lighting module, the part 1 and part 2 parameter need to be the part itself, not its position.

You would replace this:

lightningModule.CreateLightning(game.Workspace.Tower.Position, game.Workspace.Target.Position, 10)

With this:

lightningModule.CreateLightning(game.Workspace.Tower, game.Workspace.Target, 10)

Side note

Instead of doing game.Workspace you can just do workspace instead:

lightningModule.CreateLightning(workspace.Tower, workspace.Target, 10)

[Feugazi]

local lightningModule = require(game.ServerScriptService.Lightning)

lightningModule.CreateLightning(game.Workspace.Tower, game.Workspace.Target, 10)

I made this change and now receive a different error on the module:
ServerScriptService.Lightning:38: attempt to perform arithmetic (sub) on Instance - Server - Lightning:38

Fixing this error loops back to the initial index nil with 'Position' error

EDIT:
This module was based from this YouTube Video:

Summary

https://www.youtube.com/watch?v=-9S77x054Ys&t=686s

[BobbieTrooper (Jaz)]

Can u show us whats inside the module

[Feugazi]

The Module:

Summary

local module = {}

function draw(p1, p2, Parent)
	local dist = (p2.Position - p1.Position).Magnitude
	local part = Instance.new("Part", Parent)
	part.CanCollide = false
	part.Anchored = true
	part.Position = p1.Position
	part.Material = "Neon"
	part.BrickColor = BrickColor.new("New Yeller")


	part.Size = Vector3.new(.5,.5,dist)
	part.CFrame = CFrame.new(p1.Position, p2.Position) * CFrame.new(0,0,-dist/2)
	
end

module.CreateLightning = function(startPosition, endPosition, numberOfPoints)
	
	local model = Instance.new("Model",game.Workspace)
	local points = {}
	
	for i = 0,numberOfPoints do
		
		local offset = Vector3.new(math.random(-5,5),math.random(-2,2),math.random(-5,5))
		
		if i == 0 or i == numberOfPoints then
			offset = Vector3.new(0,0,0)
		end
		
		local part = Instance.new("Part", model)
		part.Anchored = true
		part.CanCollide = false
		part.Size = Vector3.new(.5,.5,.5)
		part.Material = "Neon"
		part.BrickColor = BrickColor.new("New Yeller")
		
		part.Position = startPosition + (endPosition - startPosition).Unit * i * (endPosition - startPosition).Magnitude/numberOfPoints
		points[#points+1] = part
		
	end
	
	
	for i = 1,#points do
		if points[i+1] ~= nil then
			draw(points[i], points[i-1], model)
		end
	end
	
	return model
end


return module

[BobbieTrooper (Jaz)]

I changed something in the module, i don’t know if it was the outcome you wanted to have?

module.CreateLightning = function(startPosition, endPosition, numberOfPoints)
	local model = Instance.new("Model", game.Workspace)
	local points = {}

	for i = 0, numberOfPoints do
		local offset = Vector3.new(math.random(-5,5), math.random(-2,2), math.random(-5,5))

		if i == 0 or i == numberOfPoints then
			offset = Vector3.new(0,0,0)
		end

		local part = Instance.new("Part", model)
		part.Anchored = true
		part.CanCollide = false
		part.Size = Vector3.new(.5, .5, .5)
		part.Material = "Neon"
		part.BrickColor = BrickColor.new("New Yeller")

		part.Position = startPosition + (endPosition - startPosition).Unit * i * (endPosition - startPosition).Magnitude/numberOfPoints
		points[#points+1] = part
	end

	for i = 1, #points do
		if points[i+1] ~= nil then
			draw(points[i], points[i+1], model)  -- Note the change here from points[i-1] to points[i+1]
		end
	end

	return model
end