Roblox Head Movement R15/R6 Client Only

local Camera = workspace.CurrentCamera
local Player = game.Players.LocalPlayer

local Character = Player.Character
local Root = Character:WaitForChild("HumanoidRootPart")
local Neck = Character:FindFirstChild("Neck", true)
local YOffset = Neck.C0.Y

local CFNew, CFAng = CFrame.new, CFrame.Angles
local asin = math.asin

game:GetService("RunService").RenderStepped:Connect(function()
    local CameraDirection = Root.CFrame:toObjectSpace(Camera.CFrame).lookVector
    if Neck then
        if Character.Humanoid.RigType == Enum.HumanoidRigType.R15 then
            Neck.C0 = CFNew(0, YOffset, 0) * CFAng(0, -asin(CameraDirection.x), 0) * CFAng(asin(CameraDirection.y), 0, 0)
        elseif Character.Humanoid.RigType == Enum.HumanoidRigType.R6 then
            Neck.C0 = CFNew(0, YOffset, 0) * CFAng(3 * math.pi/2, 0, math.pi) * CFAng(0, 0, -asin(CameraDirection.x)) * CFAng(-asin(CameraDirection.y), 0, 0)
        end
    end
end)