Object moving hundreds studs away from where it's supposed to be why?

This script makes a chosen part move to the position of the mouse at least it's supposed to that but isn't where the mouse is at all, the part is just hundreds of studs away from where it's supposed to be when you move your mouse around.

local script:

repeat wait() until game.Players.LocalPlayer
local UIS = game:GetService("UserInputService")
local repStorage = game:GetService("ReplicatedStorage")
local serStorage = game:GetService("ServerStorage")
local player = game.Players.LocalPlayer
local mouse = player:GetMouse()
local char = player.Character

local function round(num)
	local number = math.floor(num * 1 + 0.5) / 1
	return number
end

local placing = false
local function place(object)
	
end

local object = workspace:FindFirstChild("Model")
local function startPlacing()
	if not placing then
		object:Clone()
		placing = true
	end
end
startPlacing()

local Gridsize = 2
game:GetService("RunService").RenderStepped:Connect(function()
	if mouse then
		if mouse.Target then
			if placing then
				local x,y,z = round(mouse.X)/Gridsize, mouse.Hit ,round(mouse.Y)/Gridsize
				mouse.TargetFilter = object
				object:SetPrimaryPartCFrame(CFrame.new(x, y, z))
			end
		end
	end
end)