A roblox custom hitbox script is something every developer eventually realizes they need if they're serious about making a game that feels snappy and responsive. If you've ever played a fighting game or a sword simulator on Roblox and felt like your hits weren't registering—or worse, you were getting hit by someone standing five studs away—you've seen the limitations of the default system. Roblox's built-in .Touched event is fine for a swinging door or a simple kill-brick, but for fast-paced combat? It's just not going to cut it.
The reality is that the default physics engine handles collisions in a way that prioritizes physical simulation over competitive gameplay. When you're swinging a giant anime sword, you want the hit to feel "fair." You want it to land exactly when the blade passes through the enemy's torso. That's where writing your own logic comes into play. By taking control of how the game detects contact, you can eliminate that frustrating "clunkiness" that plagues so many amateur projects.
Why the Default Touched Event Fails You
Let's be real for a second: the .Touched event is notoriously unreliable for melee combat. Because it relies on the physics engine's collision detection, it's subject to all sorts of weirdness. If a part is moving too fast, it might skip right through an opponent without the event ever firing. If the server is lagging even slightly, the "touch" might register way after the animation has already finished.
Most high-tier developers ditch .Touched for combat almost immediately. Instead, they look toward building a roblox custom hitbox script that uses math and spatial queries to determine hits. This gives you way more control. You can define exactly when the hitbox is "active" during an animation, how big it is, and what it's allowed to hit, all without waiting for the physics engine to catch up.
Raycasting: The Sharpest Tool in the Box
One of the most popular ways to handle custom hitboxes is through raycasting. Imagine your sword has a bunch of invisible laser pointers attached to it. Every frame that you're swinging, those lasers shoot out a tiny distance. If any of those lasers hit a player's limb, boom—you've got a hit.
This method is incredibly precise. Since you're drawing lines between the sword's position in the last frame and its position in the current frame, it's almost impossible for a hit to "glitch" through a player, even at high speeds. This is often referred to as "Raycast Hitbox" logic. While there are some great community-made modules out there that do this, writing your own version helps you understand exactly how your game's "feel" is being constructed.
To make this work in your roblox custom hitbox script, you'd usually set up "attachments" along the length of your weapon. During the swing, you loop through these attachments and cast rays between their current position and where they were in the previous frame. It sounds complicated, but it's actually one of the most performant ways to handle melee detection.
Using Spatial Queries for Big Area Attacks
Sometimes raycasting is a bit too "thin." If you're making a giant explosion or a massive hammer smash, you might want something that covers a volume rather than just lines. This is where Roblox's Spatial Query API comes in—specifically functions like GetPartBoundsInBox or GetPartsInPart.
These functions allow you to define a shape in 3D space and instantly get a list of everything inside it. It's perfect for those "Area of Effect" (AoE) attacks. The beauty of using these in a roblox custom hitbox script is that you can perfectly match the hitbox to the visual effects of the move. If your character slams the ground and a shockwave goes out, you can script a cylindrical hitbox that expands along with the shockwave. It feels intuitive for the player because what they see is exactly what they get.
Client vs. Server: The Eternal Struggle
This is where things get a bit spicy. Where should your roblox custom hitbox script actually run? If you run it on the server, you have total security. No one can "cheat" their hits because the server decides everything. But there's a downside: latency. If a player has a 100ms ping, their swing will feel delayed. They'll see their sword go through an enemy, but the server won't register it until a tenth of a second later.
On the other hand, if you run the detection on the client, it feels buttery smooth. Hits register the millisecond the player sees them. But now you've opened the door to exploiters. A script kiddie could easily tell the server "Yeah, I totally hit that guy from across the map," and if your server doesn't have checks, it'll just believe them.
The "pro" way to handle this is a hybrid approach. You run the detection on the client for immediate visual feedback (like blood effects or sound), but the server still does a "sanity check." The server asks: "Is the player actually close enough to hit that target? Are they even in an attacking state?" This keeps the game feeling fast while preventing the most blatant types of cheating.
Implementing a Basic OverlapParams System
If you're looking to get started, the WorldRoot:GetPartBoundsInBox method is probably your best bet. It's modern, it's fast, and it's relatively easy to wrap your head around. You'll want to set up an OverlapParams object, which lets you filter out things you don't want to hit—like the player who is actually doing the attacking!
In your roblox custom hitbox script, you'd trigger this check during the "active" frames of your animation. You can use Animation Events to signal exactly when the hitbox should start and stop looking for targets. This prevents that awkward "lingering hitbox" bug where someone walks into your sword after the swing is over and still takes damage.
Optimizing for Performance
You might think that checking for collisions every single frame would lag the game, but Roblox is actually pretty efficient at this. However, you still want to be smart. Don't run hitbox checks on every single object in the game. Use the FilterDescendantsInstances property in your OverlapParams to only check against a specific folder of "Hittable" NPCs or players.
Also, keep your hitboxes as simple as possible. A box or a sphere is way easier for the engine to calculate than a complex mesh. Even if your sword is a jagged, weirdly shaped demon blade, your roblox custom hitbox script should probably just be checking a simple rectangular box that roughly fits the weapon's dimensions. Players won't notice the difference in shape, but they will notice if the game's frame rate starts tanking.
Visualizing for Debugging
One tip that'll save you hours of pulling your hair out: build a "Debug Mode" into your script. When you're developing, have the script spawn a semi-transparent neon part exactly where the hitbox is being calculated.
There's nothing more frustrating than wondering why your roblox custom hitbox script isn't working, only to realize the hitbox was spawning five studs behind the player because of a weird offset issue. Seeing the hitbox in real-time allows you to fine-tune the timing and size until it feels just right. Once you're happy with it, you just toggle a variable and the debug parts disappear for the final game.
Final Thoughts
At the end of the day, a roblox custom hitbox script is about player experience. The standard tools Roblox gives you are a great starting point, but they're just that—a start. Whether you decide to go with the precision of raycasting or the broad strokes of spatial queries, taking the time to script your own collision logic is what separates a "typical" Roblox game from something that feels truly high-quality.
It takes a bit of trial and error to get the math right, especially when dealing with CFrame offsets and world coordinates. But once you see your combat system working flawlessly, with every hit landing exactly where it should, you'll never go back to using .Touched again. Happy scripting!