Moving part within the boundaries?

Google Translator,sorry

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

mouse.Move:connect(function()
    workspace.Part.CFrame = CFrame.new(mouse.Hit.p.X,0.5,mouse.Hit.p.Z)

end)

How can I move a part within the boundaries of a specific object (In my case, this is part "Baseplate")? He must move freely, but he can not get out of "Baseplate"