How do you relay movement in Viewportframes?

I don't really know much about viewportframes, however what I am trying to do is have an npc appear in a frame on the player's UI with movement. I did this using the technique shown on the devforums, however all I see is a static image that doesn't move. How would I constantly update the viewportframe to show the latest position of the npc?

Here is my code, does not portray movement:

local player = game.Players.LocalPlayer
local vp = player:WaitForChild("PlayerGui"):WaitForChild("CountDown"):WaitForChild("Members").Frame.ViewportFrame
local obj = workspace.TestSubject
local camera = Instance.new("Camera")

obj.Parent = vp
camera.Parent = vp
vp.CurrentCamera = camera

local pos = obj.PrimaryPart.Position + obj.PrimaryPart.CFrame.LookVector*6
local lookAt = obj.PrimaryPart.Position

camera.CFrame = CFrame.new(pos + Vector3.new(0,1,0), lookAt)

I am 100% sure this is not the most efficient way to do this, but I ended up cloning the model and constantly deleting and recloning it. I would probably also use the RunService for this. If anyone knows a better way please feel free to answer.

local player = game.Players.LocalPlayer
local vp = player:WaitForChild("PlayerGui"):WaitForChild("CountDown"):WaitForChild("Members").Frame.ViewportFrame
local obj = workspace.TestSubject
local camera = Instance.new("Camera")
local prevObj

camera.Parent = workspace
vp.CurrentCamera = camera


while true do
	local newObj = obj:Clone()
	newObj.Parent = vp
	
	if prevObj then prevObj:Destroy() end
	
	prevObj = newObj
	
	local pos = obj.PrimaryPart.Position + obj.PrimaryPart.CFrame.LookVector*6
	local lookAt = obj.PrimaryPart.Position
	
	camera.CFrame = CFrame.new(pos + Vector3.new(0,1,0), lookAt)
	wait()
end