Realistic Dynamic Movement R15

-- In StarterCharacterScript

--//Variables
local Player = game.Players.LocalPlayer
local Camera = workspace.CurrentCamera
local Character = Player.Character or Player.CharacterAdded:Wait()
local Humanoid = Character:WaitForChild("Humanoid")
local rootPart = Character.PrimaryPart
local upperTorso = Character:WaitForChild("UpperTorso")
local waistJoint = upperTorso:WaitForChild("Waist")

local currentSpeed = 0
local currentTween = nil

--//Services
local UIS = game:GetService("UserInputService")
local RunService = game:GetService("RunService")
local TweenService = game:GetService("TweenService")

--//Code
Humanoid.Running:Connect(function(speed)
    currentSpeed = speed
end)

local orginalWaistC1 = waistJoint.C1
local maxRotation = math.rad(65)
RunService:BindToRenderStep("vanityCamera", 400, function()
    local TargetPos = (Camera.CFrame * CFrame.new(0,0,-1000)).p
    local TorsoFront = rootPart.CFrame.LookVector
    local TorsoRight = rootPart.CFrame.RightVector
    local vectorToTarget = (TargetPos - rootPart.Position)
    local rotation = math.atan2(TorsoRight:Dot(vectorToTarget), TorsoFront:Dot(vectorToTarget))

    if (rotation < -maxRotation) then
        rotation = -maxRotation
    elseif (rotation > maxRotation) then
        rotation = maxRotation
    end

    if (math.abs(rotation) == maxRotation and currentSpeed <= 0.5) then
        local newRootPartCFrame = CFrame.new(rootPart.Position, Vector3.new(TargetPos.X, TargetPos.Y, TargetPos.Z))
        currentTween = TweenService:Create(rootPart, TweenInfo.new(0.33), {
            CFrame = newRootPartCFrame
        })
        currentTween:Play()
    else
        if (currentTween and currentSpeed > 0.5) then
            if (currentTween.PlaybackState == Enum.PlaybackState.Playing) then
                currentTween:Cancel()
            end
        end
        waistJoint.C1 = CFrame.Angles(0, rotation, 0) * orginalWaistC1
    end
end)