Why won't my placement system work? It won't place anything

Alright, so since the release of miners haven code, i wanted to redo my sandbox tycoon system(because, 100 lines of code, i can now do in 75 lines.). I'm trying to block placement that is colliding with other parts, BUT i don't really know how to use :GetTouchingParts.

I've tried using it, but i dun know how to use it:

mah code

client crap and stuff

local player = game.Players.LocalPlayer
    local mouse = player:GetMouse()

local PosX 
local PosY 
local PosZ 

local model1= game.ReplicatedStorage.Items.Test

local model = model1:Clone()
    model.Parent = workspace

local gridsize = 2

local touchingparts

local function snap()
    PosX = math.floor(mouse.Hit.X / gridsize + 0.5) * gridsize 
    PosZ = math.floor(mouse.Hit.Z / gridsize + 0.5) * gridsize 
    PosY = model.PrimaryPart.Position.Y 
end

mouse.Move:Connect(function()
    mouse.TargetFilter = model
    snap()
    for i, children in pairs(model:GetChildren()) do
        if children:IsA("BasePart") then
            children.Transparency = 0.5
            children.CanCollide = false 
        end
    end
    model:SetPrimaryPartCFrame(CFrame.new(PosX, PosY, PosZ))
end)


mouse.Button1Down:Connect(function()
    touchingparts = model.PrimaryPart:GetTouchingParts()

    if not touchingparts then
        game.ReplicatedStorage.Remotes.PlaceObj:FireServer(PosX, PosY, PosZ, model1)
    end
end)

server script(i've removed leaderstats from this script)

local rp = game:GetService("ReplicatedStorage")
    local items = rp.Items
    local modules = rp.Modules
    local remotes = rp.Remotes


remotes.PlaceObj.OnServerEvent:Connect(function(plr, posx, posy, posz, model)
    local newmodel = model:Clone()
    newmodel:SetPrimaryPartCFrame(CFrame.new(posx, posy, posz))
    newmodel.Parent = workspace
end)