If you're trying to track when a player jumps, falls, or lands, getting a roblox studio humanoid state changed script up and running is usually the first thing you'll need to do. It's one of those foundational pieces of logic that sounds simple on paper but can get a little finicky if you don't know how Roblox handles physics states under the hood. Most of the time, we're just looking for a way to trigger an animation or a sound effect when someone hits the ground, but this event can do a whole lot more than that if you set it up right.
Why this event is a lifesaver
When you're building a game, you constantly need to know what the player is actually doing. Is representatively "walking"? Are they "freefalling"? Maybe they just sat down in a vehicle? Instead of running a loop that checks the player's status every single frame—which is a total resource hog, by the way—Roblox gives us the StateChanged event.
It's basically a built-in listener that waits for the Humanoid to change its mind about what it's doing. When the engine decides the player is no longer "Running" and is now "Jumping," it fires this event. It's efficient, it's clean, and it keeps your game from lagging out because you aren't constantly polling the physics engine for updates.
Setting up the basic script
To get started, you'll usually want this script inside StarterCharacterScripts. This ensures that every time a player spawns, they get a fresh copy of the logic. If you put it in a regular Script or a LocalScript, the setup is mostly the same, but for character-specific movement, StarterCharacterScripts is the path of least resistance.
Here's a simple way to lay it out:
```lua local character = script.Parent local humanoid = character:WaitForChild("Humanoid")
humanoid.StateChanged:Connect(function(oldState, newState) print("Player went from " .. oldState.Name .. " to " .. newState.Name) end) ```
This tiny bit of code is enough to show you exactly what's happening in the output window. You'll notice that as you move around, the states flip-flop between things like Running, PreManeuver, Jumping, and Freefall. It's actually pretty cool to see how the engine "thinks" about your movement in real-time.
Understanding the parameters
You might have noticed oldState and newState in the function. These are Enums, which is just a fancy way of saying they are predefined labels Roblox uses.
The oldState tells you what the player was doing, and newState tells you what they just started doing. This is super helpful for logic like fall damage. You don't want to hurt the player just because they are in the Landed state; you only want to hurt them if the oldState was Freefall and they were falling for a long time.
Practical Example: Custom Landing Effects
Let's say you want to make a "thud" sound or a dust particle effect happen when a player hits the ground after a big jump. You wouldn't want this to happen every time they take a step, so you have to be specific about which states you're looking for.
```lua local humanoid = script.Parent:WaitForChild("Humanoid")
humanoid.StateChanged:Connect(function(oldState, newState) if newState == Enum.HumanoidStateType.Landed then print("The player hit the ground!") -- This is where you'd trigger your sound or particles end end) ```
In a lot of cases, the Landed state is exactly what you need. However, keep in mind that sometimes Roblox skips Landed and goes straight back to Running if the player is moving quickly. It's one of those weird quirks you'll run into. If Landed isn't firing reliably for you, you might want to check if the newState is Running while the oldState was Freefall.
Common states you'll actually use
There are a bunch of Humanoid states, but honestly, you'll only use about four or five of them regularly.
- Running: This is the default. Even if the player is standing still, the state is often "Running" but with a speed of zero.
- Jumping: Fires the moment the spacebar is hit or the jump power is applied.
- Freefall: This happens when the player is in the air but not moving upward from a jump. It's great for detecting if someone walked off a cliff.
- Landed: This is the brief moment of impact with a surface.
- Swimming: Self-explanatory, but useful if you want to change the UI or lighting when they dive into water.
If you're making a platformer, you might also care about Climbing. It's really handy for disabling certain attacks or abilities while the player is on a ladder.
Dealing with the "Physics Jitters"
One thing that drives developers crazy when working with a roblox studio humanoid state changed script is how often it can fire. If a player is walking over slightly uneven terrain or a pile of small parts, the physics engine might get confused. It might think the player is "Freefalling" for 0.01 seconds and then "Landed" again, over and over.
If you're triggering a loud sound effect on the Landed state, this can result in a machine-gun sound of "thud-thud-thud-thud" as they walk over a bumpy floor.
To fix this, you can use a "debounce" or a small timer. Basically, tell the script: "If you just played the landing sound, wait at least half a second before playing it again." It makes the game feel much more polished and less like a glitchy mess.
Performance and Debouncing
Speaking of performance, don't go overboard with what you put inside the StateChanged function. If you're doing heavy calculations or searching through the entire workspace every time a player takes a step, you're going to see some frame drops.
Keep the logic light. Use it to flip booleans, start/stop animations, or fire a RemoteEvent to the server if necessary. If you need to do something big, like changing the entire map's lighting because the player entered a "Swimming" state, maybe add a check to make sure the state actually changed to something different before running the code.
```lua local lastState = nil
humanoid.StateChanged:Connect(function(_, newState) if newState == lastState then return end lastState = newState
-- Now run your logic safely end) ```
Even though the event itself usually handles this, sometimes the engine re-registers the same state twice in a row due to physics updates. A little safety check never hurts.
Wrapping it up
The roblox studio humanoid state changed script is a tool that every scripter eventually needs to master. Whether you're building a hardcore parkour game or just want your character to make a splashing sound in the pool, understanding how to listen to these state transitions is key.
It's one of those things where you'll probably spend more time testing and tweaking the feel of the states than actually writing the code. Physics can be weird, and players will always find ways to break your movement logic by jumping into corners or sliding down ramps. But once you get the hang of filtering for the right newState, you'll have much more control over how your characters interact with the world.
Just remember to keep an eye on that Landed vs Running transition, and don't be afraid to use print() statements to see what the engine is doing while you're playtesting. Happy scripting!