how on earth do i make a player change animation when it hits a walkspeed? (UNANSWERED)

The script is a little bit wrong here, and it's in a place where it won't work.

I'd prefer putting this script i'll post down as a normal script or a localscript, in game > StarterPlayer > StarterCharacterScripts

Btw, a localplayer cant be found in a normal script. You can only do localplayer in a localscript.

      local Humanoid = script.Parent:FindFirstChild("Humanoid") -- check for humanoid inside player

        local RunAnimation = Instance.new('Animation')  
        RunAnimation.AnimationId = 'rbxassetid://3518952951'
    RAnimation = Humanoid:LoadAnimation(RunAnimation)

    if Humanoid.Walkspeed == 25 then
        RAnimation:Play()
    elseif Humanoid.Walkspeed == 4 then
        RAnimation:Stop()
    end

Your script was nearly correct, but it was just in the wrong place. Unless it was getting cloned into players.

Edit: Made a mistake.

Downest have the answer :)

You need to change the StarterPlayer's walk speed so it will work.

Line 9 - 13 will give big problems :(

You should change it to this :

if Humanoid.Walkspeed == 25 then
    RAnimation:Play()
    RunAnimation:Stop()
elseif Humanoid.Walkspeed == 4 then
    RAnimation:Stop()
    RunAnimation:Play()
end

You didn't stop the RAnimation but you stopped the RunAnimation so it didn't work

So this is the entire script :

local Player = game.Players.LocalPlayer
    local Character = workspace:WaitForChild(Player.Name)
        local Humanoid = Character:WaitForChild('Humanoid')

local RunAnimation = Instance.new('Animation')
RunAnimation.AnimationId = 'rbxassetid://3518952951'
RAnimation = Humanoid:LoadAnimation(RunAnimation)

if Humanoid.Walkspeed == 25 then
    RAnimation:Play()
    RunAnimation:Stop()
elseif Humanoid.Walkspeed == 4 then
    RAnimation:Stop()
    RunAnimation:Play()
end

Hope I helped, thanks for reading and bye!

The easiest way would be to do the animation from a serverscript like you were doing and have it in ServerScriptService. I also want to tell you that game.Players.LocalPlayer is only available to LocalScripts. If you think about it, the serverscript in serverscriptservice doesn't have a "LocalPlayer". Another thing, it's best to do playerInstance.Character as this will give you the character straightup, if someone has the same name as something in the workspace, there could be errors. I wrote the code below and I'll explain it with comments.

local RunAnimation = Instance.new('Animation') --Animation instance
RunAnimation.AnimationId = 'rbxassetid://3518952951'

local function check(humanoid, RAnimationReturned)
    local RAnimation = humanoid:LoadAnimation(RunAnimation) --Load the animation with the characters humanoid
    RAnimation.Priority = 'Action'
    if humanoid.Walkspeed > 4 and RAnimatioReturned == nil then --If their walkspeed is over 4, then play the animation
        RAnimation:Play()
        return RAnimation --Return the animation so it can be stopped later
    elseif RAnimationReturned ~= nil and humanoid.Walkspeed <= 4 then
        RAnimationReturned:Stop() --Stop the animation, this variable is the one that was returned from an earlier execution of this function
    end
end

game.Players.PlayerAdded:Connect(function(plr) --Everytime a player is added to the game
    local humanoid = plr.Character:WaitForChild('Humanoid')
    local RAnimation = check(humanoid, nil) --Play the function once to start up everything
    humanoid:GetPropertyChangedSignal('Walkspeed'):Connect(function() --Anytime the player's walkspeed changes, do the check function
        RAnimation = check(humanoid, RAnimation)
    end)
end)

This should work, but tell me if you're getting any errors or something isn't working right