Building a roblox custom fall damage script is one of those small changes that makes a massive difference in how your game actually feels to play. Let's be real, the default Roblox health system is fine for a basic obby, but it's pretty boring. It doesn't give you much control over the "thud" factor. If you're working on a survival game, a hardcore shooter, or a movement-based platformer, you probably want something more nuanced than the "all-or-nothing" damage that comes out of the box.
Why bother with a custom setup? Well, maybe you want players to take more damage if they're carrying heavy loot, or perhaps you want to trigger a "broken leg" animation that slows them down for a few seconds. Whatever your reason, getting under the hood and writing your own logic is the best way to move away from that generic "unbranded" feel many games have.
Why the Default System Usually Falls Short
If you've spent any time in Studio, you know that the default Humanoid behavior is pretty rigid. You can toggle FallDamage in some templates, but you don't get a say in the math. It's a very linear relationship. In the real world (and in high-quality games), falling from two stories shouldn't just tick off a bit of health; it should feel impactful.
By using a roblox custom fall damage script, you gain the power to define "lethality." You can decide that any fall over 50 studs is an instant kill, or you can make it so that falling into water completely negates the damage. You can't easily do that with the default settings. Plus, the default system doesn't always account for different gravity settings or character scales, which can lead to some really weird bugs if you're making a game set on the moon or playing as a giant.
The Logic Behind the Fall
Before you start typing out lines of code, it helps to understand how Roblox even knows a player is falling. The Humanoid object has a property called FloorMaterial. When that material changes to Air, the player is officially in flight. But a better way to track this for damage purposes is by watching the HumanoidState.
There are two main ways to calculate damage: Velocity-based and Height-based.
Height-based is the classic way. You record the Y-coordinate of the player when they start falling and compare it to the Y-coordinate when they land. The difference is your distance. It's easy to understand, but it can be buggy if the player is blown upward by an explosion or uses a jump pad.
Velocity-based is generally considered the "pro" way to do it. You check how fast the player is moving downward (their Y-velocity) the moment they hit the ground. If they hit the ground at a high speed, they take a lot of damage. This feels much more natural because it handles things like falling while already moving fast or being slammed into the ground by a physics object.
Setting Up a Basic Script
To get started, you'll usually want to put your script in StarterCharacterScripts so it loads every time a player's character spawns. Since we want this to be secure, we usually handle the actual health reduction on the server, but the detection can happen on the client for better responsiveness—though that opens the door for exploiters. For a standard project, a single Server Script inside the character is a solid middle ground.
You'll want to hook into the StateChanged event. This event fires whenever the player goes from jumping to falling, or falling to landed. When the state changes to Landed, that's your cue. You look at how long they were in the Freefall state or how fast they were moving right before the state switched.
Making it Feel "Juicy"
A script that just subtracts a number from a health bar is "functional," but it isn't "good." To make your roblox custom fall damage script stand out, you need to add what developers call "juice."
Think about what happens when you hit the ground in a modern AAA game. The camera shakes, the audio dips into a muffled "thump," and maybe the edges of the screen flash red. You can script all of this! You can trigger a RemoteEvent that tells the player's client to play a "bone crunch" sound effect and shake the camera based on how much damage was taken. If the damage is over 50%, maybe you blur their vision for a second. This feedback tells the player, "Hey, you messed up," far better than a shrinking green bar ever could.
Handling the Edge Cases
This is where things get a bit tricky. If you've ever played a game where you died because you stepped off a tiny curb the wrong way, you know how frustrating bad fall damage math can be.
One big issue is "wall-sliding." If a player is rubbing against a wall while falling, their velocity might stay low, but they're still technically in a Freefall state. Your script needs to be smart enough to handle that. Another issue is lag. If a player's internet spikes right as they land, the server might think they're still falling, leading to a "teleportation" death where they take damage five seconds after they've already started running again.
To fix this, you can implement a "grace period" or a minimum threshold. Don't even bother calculating damage for falls under 10 or 15 studs. It keeps the game feeling fluid and prevents those annoying "micro-damage" ticks that happen when navigating rocky terrain.
Preventing Exploits
Let's talk about the elephant in the room: cheaters. If you handle all your fall damage logic on the client (LocalScript), an exploiter can literally just delete the script or change the variables so they never take damage. They could jump off the tallest building in your game and land like a feather.
To stop this, you should keep the core logic on the server. While the server's view of the player isn't perfectly frame-accurate compared to the player's own screen, it's "close enough" for fall damage. By checking the player's velocity on the server side, you ensure that even if the player modifies their local files, the server sees them slamming into the ground at 100 miles per hour and applies the damage accordingly.
Adding Advanced Features
Once you have the basics down, you can start adding the cool stuff. For example, what if you have different surfaces? You could check the FloorMaterial property we mentioned earlier. If the player lands on Fabric (like a carpet or a mat), you could reduce the damage by 50%. If they land on Water, you could cancel it entirely.
You can also incorporate character stats. If your game has a "Stamina" or "Agility" attribute, you could use that to calculate a "roll" chance. A player with high agility might have a 30% chance to "roll" out of a fall, taking half damage and playing a cool animation instead of the standard landing.
Final Thoughts on Implementation
When you're finally writing your roblox custom fall damage script, remember that game feel is more important than "realistic" physics. In the real world, falling 20 feet is a trip to the hospital. In a video game, that might just be a minor inconvenience.
Test your script repeatedly. Jump off different heights, try to "cheat" the system by sliding down slopes, and see how it feels. If the damage feels too punishing, dial it back. If it feels like there are no stakes, crank it up.
Coding your own systems is how you transition from being a "map maker" to a "game developer." It gives you total control over the player's experience. So, open up Studio, create a new script, and start playing around with those humanoid states. You'll be surprised at how much better your game feels once the physics actually have some weight to them. Don't be afraid to break things—that's usually how you find the coolest mechanics anyway!