Getting your UI or camera to react perfectly to a roblox mousemove event is one of those things that seems simple until you're staring at a jittery cursor or a menu that won't close. If you've spent any time in Roblox Studio, you know that player input is the heart of everything. Without a solid way to track where the player is looking or pointing, your game just feels well, stiff.
Most people start by using the old-school Mouse object, which has been around since the early days of Roblox. It's fine for basic stuff, but if you're trying to build something that feels modern and professional, you're going to want to dive into UserInputService. It gives you way more control and doesn't feel like you're fighting against legacy code every five minutes.
Why the old Mouse object is a bit of a trap
When you first start scripting, someone probably told you to just use Player:GetMouse(). It's tempting. It has a Move event that fires whenever the mouse moves, and it's very straightforward. But here's the thing: it's kind of outdated. Roblox hasn't really updated the Mouse object in years because they want everyone to move toward UserInputService (UIS) and ContextActionService.
The problem with the legacy roblox mousemove approach is that it's not very flexible. It doesn't play nice with gamepads or touchscreens, and if you're planning on making your game cross-platform—which you definitely should—you'll find yourself writing a ton of extra code to fix things that UIS handles natively. Plus, the old Mouse.Move doesn't give you as much raw data as the newer methods do.
Setting up UserInputService for movement
If you want to track movement the right way, you should be looking at the InputChanged event. This is the gold standard for anything related to a roblox mousemove trigger. It fires for a lot of different things, so you have to filter it down to just the mouse.
It usually looks something like this: You connect a function to game:GetService("UserInputService").InputChanged, and then you check if the input.UserInputType is equal to Enum.UserInputType.MouseMovement.
The cool part about doing it this way is that you get access to the Delta. If you've ever wondered how first-person camera systems work without the mouse actually hitting the edge of the screen, it's because of the delta. It tracks how much the mouse moved since the last frame, rather than just its absolute position on the screen. This is a game-changer for custom camera scripts.
Dealing with the 36-pixel offset headache
This is a classic "welcome to Roblox" moment for new developers. You write a script to place a UI element exactly where the mouse is, and you notice it's always a little bit lower than it should be. It's infuriating until you realize why it's happening.
Roblox has a "TopBar"—that little translucent strip at the top where the chat and menu buttons live. By default, the GUI coordinate system starts below that bar, but the roblox mousemove position is often calculated from the very top of the window. This creates a 36-pixel offset.
To fix it, most devs use GuiService:GetGuiInset(). This tells you exactly how big that top bar is, so you can subtract it from the mouse's Y-position. Once you do that, your custom cursors or inventory drag-and-drop systems will finally line up perfectly. It's a small detail, but skipping it makes a game feel incredibly unpolished.
Custom cursors and hover effects
Speaking of polish, let's talk about custom cursors. Using the default white arrow is fine for a simulator, but if you're making a horror game or a stylized RPG, you want something unique.
Instead of just changing the Mouse.Icon property (which is often blurry and hard to control), a lot of top-tier devs hide the default mouse entirely using UserInputService.MouseIconEnabled = false and then move an ImageLabel to the mouse's position. This is where your roblox mousemove logic really shines. You update the position of that ImageLabel every time the mouse moves.
Pro tip: Use RenderStepped for updating custom cursors instead of just the InputChanged event. InputChanged only fires when the mouse moves, but RenderStepped ensures the cursor position updates every single frame. This makes the movement look buttery smooth even if the player is moving their mouse at lighting speed.
Performance: Don't kill your frame rate
One thing you have to be careful about is what you put inside your roblox mousemove functions. These events fire a lot. If a player has a high-polling-rate mouse (like 1000Hz), that event could be firing hundreds of times a second.
If you're running heavy math, raycasting, or updating 50 different UI elements inside that function, you're going to see your frame rate tank. You want to keep the logic inside these events as "lean" as possible.
If you absolutely need to do something heavy, like figuring out what 3D object the player is pointing at, consider "throttling" the logic. You don't need to raycast 1000 times a second. You could use a simple debounce or only run the expensive logic every 0.05 seconds. The player won't notice the difference, but their CPU certainly will.
Raycasting from the mouse position
Probably the most common use for tracking a roblox mousemove is to interact with the 3D world. Whether it's clicking on an NPC or highlighting a door when the player looks at it, you're going to need raycasting.
The modern way to do this is using Camera:ViewportPointToRay(). You take the X and Y coordinates from your mouse movement, feed them into that function, and it spits out a Ray that shoots from the camera into the world.
It's way more reliable than the old Mouse.Target property. Why? Because Mouse.Target ignores certain things and can be buggy with transparent objects or specific collision groups. With ViewportPointToRay, you have total control over what the "mouse" can actually see and hit by using RaycastParams.
Cross-platform considerations
We can't talk about mouse movement without mentioning that a huge chunk of Roblox players are on phones or tablets. Obviously, they don't have a roblox mousemove event in the traditional sense. They have touch inputs.
This is why UserInputService is so much better than the legacy Mouse object. You can write your code to handle both MouseMovement and Touch. If you're building a system where the player drags an item across the screen, the logic is almost identical for both.
If you only script for the mouse, you're cutting out a massive portion of your potential player base. Always test your movement logic in the "Device Emulator" in Studio. If your hover effects or drag-and-drop systems don't work with a finger tap, it's time to go back to the drawing board.
Making menus feel alive
One of my favorite uses for roblox mousemove is adding a slight "tilt" to UI menus. You see this in a lot of high-end games where the main menu shifts slightly depending on where your cursor is. It's a subtle effect, but it makes the UI feel like it exists in a 3D space.
To do this, you calculate how far the mouse is from the center of the screen. You then use that distance to rotate the UI frames by just a few degrees. It's a simple bit of math, but the impact on the "feel" of the game is huge. It takes a boring, flat menu and makes it feel interactive and premium.
Debugging mouse issues
We've all been there—your mouse script just stops working. Usually, it's because a GUI element is blocking the input. If you have a full-screen frame with Active set to true, it might "swallow" the mouse events, preventing your scripts from seeing the movement.
Whenever I'm troubleshooting a roblox mousemove issue, the first thing I do is throw a print() statement inside the event. If it's not printing, something is blocking the input or the script isn't running at all. If it is printing but the position looks weird, I check the GuiInset or the AbsolutePosition of the parent frames.
It's also worth checking if you're accidentally using LocalPlayer code in a Script instead of a LocalScript. Mouse movement is strictly a client-side thing. The server doesn't know where the player's mouse is unless you tell it via a RemoteEvent, and honestly, you should avoid sending mouse coordinates to the server too often unless you want to set your bandwidth on fire.
Final thoughts on smooth interaction
At the end of the day, handling a roblox mousemove isn't just about making things work; it's about making them feel good. The best games on the platform are the ones where you don't even think about the controls because they're so intuitive.
Whether you're building a complex building system, a snappy FPS, or just a nice-looking shop menu, take the time to get your mouse logic right. Use UserInputService, watch out for that 36-pixel offset, and always keep performance in mind. Your players might not consciously notice that the custom cursor is perfectly synced to the frame rate, but they'll definitely feel the difference if it isn't. Happy scripting!