Need help on moving Models Using Tween Service

[rekishki (Durr)]

So I was following a YouTube tutorial about moving a model using TweenService because I wanted to make the set of buildings move so I could make an illusion that the bus is moving. I just came back scripting from a long time so I must have missed or overlooked something but please let me know.

I made sure that I followed what I need to follow in the video but for some reason
I was given this error:

Workspace.SpawnBus.CityBuildings.MoveScript:10: attempt to index nil with 'PrimaryPart'

The model “BuildingSet1” already has a primary part, so I don’t know what is nil.

My Script:

local BuildingSet1 = script.Parent:WaitForChild("BuildingSet1")
local BuildingSet2 = script.Parent:WaitForChild("BuildingSet2")
local TweenService = game:GetService("TweenService")

local function MoveSet1(BuildingSet1)
	local TweenInfo1 = TweenInfo.new(5, Enum.EasingStyle.Sine,Enum.EasingDirection.InOut, -1)
	local Cframe1 = Instance.new("CFrameValue")
	Cframe1.Value = BuildingSet1:GetPrimaryPartCFrame() -- Where I got the error
	Cframe1:GetPropertyChangedSignal("Value"):Connect(function()
		BuildingSet1:GetPrimaryPartCFrame(Cframe1.Value)
	end)
	local Tween1 = TweenService:Create(Cframe1,TweenInfo1, {Value = CFrame.new(-1053.61, 11.9, -839.46)})
	Tween1:Play()
	wait(1)
end

MoveSet1()

[Dimon9lul (Dimon)]

I have solved a similar case in the past, but it has nothing to do with tweening. Here you see the conversation: Tweening in a circle

[rekishki (Durr)]

It’s a good idea but the problem is when I run it it causes the game to lag a lot and it’s harder to change the position smoother, which is why I prefer using tween service because it is able to make a smooth movement.

anyways I was able to solve it:

new script:

local BuildingSet1 = script.Parent:WaitForChild("BuildingSet1")
local BuildingSet2 = script.Parent:WaitForChild("BuildingSet2")
local TweenService = game:GetService("TweenService")

print(workspace.SpawnBus.CityBuildings.BuildingSet1.PrimaryPart.CFrame)

local function MoveSet1(BuildingSet1)
	local TweenInfo1 = TweenInfo.new(5, Enum.EasingStyle.Sine,Enum.EasingDirection.InOut, -1)
	local Cframe1 = Instance.new("CFrameValue")
	Cframe1.Value = workspace.SpawnBus.CityBuildings.BuildingSet1.PrimaryPart.CFrame -- Where I got the error
	Cframe1:GetPropertyChangedSignal("Value"):Connect(function()
		workspace.SpawnBus.CityBuildings.BuildingSet1:SetPrimaryPartCFrame(Cframe1.Value)
	end)
	local Tween1 = TweenService:Create(Cframe1,TweenInfo1, {Value = CFrame.new(-1053.61, 11.9, -839.46)})
	Tween1:Play()
	wait(1)
end

MoveSet1()

apparently, I think the problem is the function doesn’t know what “BuildingSet1”.

But thanks for the help.