Easy Fly

local Players = game:GetService("Players")
local UserInputService = game:GetService("UserInputService")
local RunService = game:GetService("RunService")

local CurrentCamera = workspace.CurrentCamera

local LocalPlayer = Players.LocalPlayer

local Boolean = false
local Speed = 50
local MovementTable = {
    0,
    0,
    0,
    0,
    0,
    0
}
local KeyCodeTable = {
    [Enum.KeyCode.W] = 1,
    [Enum.KeyCode.A] = 2,
    [Enum.KeyCode.S] = 3,
    [Enum.KeyCode.D] = 4,
    [Enum.KeyCode.LeftControl] = 5,
    [Enum.KeyCode.Space] = 6
}

UserInputService.InputBegan:Connect(function(Input, ...)
    if Input.KeyCode == Enum.KeyCode.F then
        if Boolean then
            Boolean = false
        else
            Boolean = true
        end
    elseif Input.KeyCode == Enum.KeyCode.LeftShift then
        Speed = 100
    elseif KeyCodeTable[Input.KeyCode] then
        MovementTable[KeyCodeTable[Input.KeyCode]] = 1
    end
end)

UserInputService.InputEnded:Connect(function(Input, ...)
    if Input.KeyCode == Enum.KeyCode.LeftShift then
        Speed = 50
    elseif KeyCodeTable[Input.KeyCode] then
        MovementTable[KeyCodeTable[Input.KeyCode]] = 0
    end
end)

local GetMass = function(Model)
    local Mass = 0
    for _, Value in pairs(Model:GetDescendants()) do
        if Value:IsA("BasePart") then
            Mass = Mass + Value:GetMass()
        end
    end
    return Mass * workspace.Gravity
end

RunService.RenderStepped:Connect(function(...)
    local Character = LocalPlayer.Character
    if Character then
        local HumanoidRootPart = Character:FindFirstChild("HumanoidRootPart")
        local Mass = GetMass(Character)
        if HumanoidRootPart then
            local BodyVelocity = HumanoidRootPart:FindFirstChildOfClass("BodyVelocity")
            if BodyVelocity then
                if Boolean then
                    BodyVelocity.MaxForce = Vector3.new(Mass * Speed, Mass * Speed, Mass * Speed)
                    BodyVelocity.Velocity = CurrentCamera.CFrame.LookVector * Speed * (MovementTable[1] - MovementTable[3]) + CurrentCamera.CFrame.RightVector * Speed * (MovementTable[4] - MovementTable[2]) + CurrentCamera.CFrame.UpVector * Speed * (MovementTable[6] - MovementTable[5])
                else
                    BodyVelocity.MaxForce = Vector3.new(0, 0, 0)
                    BodyVelocity.Velocity = Vector3.new(0, 2, 0)
                end
            end
        end
    end
end)