If you're building a home-design game or a classic tycoon, getting your roblox furniture placement system script right is usually the first big hurdle you'll face. It's one of those features that looks simple from the outside—you just click and a chair appears, right?—but once you start digging into the code, you realize there's a lot of math and logic working behind the scenes. You have to handle everything from grid snapping and rotation to making sure players aren't shoving refrigerators through solid brick walls.
The good news is that once you understand the basic logic, it's not as intimidating as it looks. You don't need to be a math genius, but you do need to get comfortable with Raycasting and CFrames. Let's break down how to put one of these together without losing your mind in the process.
The logic behind the placement
Before you even touch a script, you have to think about how the game actually "sees" where the player wants to put an item. Most developers use the player's mouse position to determine the placement. However, the mouse just points at a spot on the screen; you need to translate that 2D point into a 3D coordinate in your game world.
This is where Raycasting comes in. Your roblox furniture placement system script will basically fire an invisible laser beam from the camera through the mouse cursor. When that beam hits the floor or a wall, it returns a position. That's your starting point. But you can't just slap a model at that exact coordinate, or it might end up halfway buried in the ground. You have to account for the size of the furniture and the orientation of the surface it's sitting on.
Setting up the grid snapping
Unless you're making a super-realistic sandbox where items can be placed anywhere down to the millimeter, you're probably going to want a grid system. It makes building much more satisfying for the player. Without a grid, it's almost impossible to line up two sections of a wall or place four chairs evenly around a table.
The math for a grid is actually pretty straightforward. If you want a 1-stud or 2-stud grid, you take the position your Raycast found and round it. For example, if your mouse is at 10.7, 5, 3.2 and you're using a 2-stud grid, you'd round those numbers to the nearest multiple of two. In Luau, you'd use something like math.floor(position / gridSize + 0.5) * gridSize.
It sounds fancy, but it just forces the item to "snap" to the imaginary squares on your floor. It feels much cleaner and prevents that messy, overlapping look that ruins the vibe of a well-designed room.
Handling rotation and user input
A furniture system is pretty useless if everything has to face north. You need to give players the ability to spin their items around. Usually, this is handled by listening for a keypress—most Roblox games use "R" for rotation.
In your roblox furniture placement system script, you'll want to keep a variable that tracks the current rotation (like 0, 90, 180, or 270 degrees). Every time the player hits R, you add 90 to that variable. Then, when you're calculating the final CFrame for the furniture model, you multiply the position CFrame by an angle CFrame.
One thing that trips up a lot of people is the pivot point. If your furniture model's primary part isn't centered correctly, it'll swing wildly around the room when you rotate it instead of spinning in place. It's a good idea to make sure all your models are set up with a clean PrimaryPart before you even start scripting.
The ghost preview effect
Nobody likes placing something blindly and hoping it lands in the right spot. You need a "ghost" or "phantom" version of the item that follows the mouse around before the player clicks to confirm.
To do this, you'll want to clone the furniture model when the player selects it and move it to the mouse's position every frame using a RunService.RenderStepped loop. You'll also want to make this preview slightly transparent and maybe change its color. If the placement is valid, make it a nice semi-transparent blue or green. If the player is trying to put a bathtub on the ceiling or inside a wall, turn it red. This kind of visual feedback is what makes a game feel "pro" rather than something just thrown together.
Dealing with collisions and boundaries
This is usually the part that gives scripters the most headaches. How do you stop players from stacking twenty chairs on top of each other or placing a bed halfway through a wall?
There are a few ways to handle this. Some people use the GetPartsInPart function to see if the preview model is touching anything it shouldn't be. Others use a simpler bounding box check. If your roblox furniture placement system script detects a collision, you set a "canPlace" variable to false and prevent the player from clicking.
You also have to think about the "Plot" or the area where the player is allowed to build. You don't want someone decorating the entire map or stealing their neighbor's living room. You can check if the mouse's hit position is within the bounds of the player's specific plot area before allowing any placement to happen.
Client vs. Server: Keeping it secure
If you run your entire placement system on a LocalScript, it'll be fast and responsive, but nobody else will see the furniture. Plus, exploiters will have a field day. You have to split the work.
- The Client (LocalScript): Handles the mouse movement, the ghost preview, the grid snapping math, and the input detection. It's all about the "feel."
- The Server (Script): When the player clicks to place, the client sends a RemoteEvent to the server with the item name, the position, and the rotation.
- The Verification: The server must check the data. Don't just trust the client! The server should check if the player actually owns that item, if they are close enough to the plot, and if the position is actually valid.
If everything looks good, the server spawns the actual model and parents it to the workspace. This keeps the game fair and ensures everyone can see the cool new house the player just built.
Polishing the experience
Once you have the basic roblox furniture placement system script working, it's time to add the "juice." Small things like a subtle sound effect when an item snaps into place or a little puff of particles when something is placed can make a huge difference.
You might also want to add a "Delete" or "Move" mode. Moving is basically just re-triggering the placement logic but starting with an existing model instead of a new one. Deleting is even simpler—just fire a RemoteEvent that tells the server to destroy the specific model the player is clicking on.
Final thoughts on optimization
If you've got a server with 50 people all placing furniture at once, things can get laggy if you're not careful. Avoid doing heavy calculations on the server inside loops. Keep the server's job simple: verify and create. Let the player's computer do the heavy lifting of moving the ghost preview around.
Also, make sure you're using TargetFilter. When the player is moving an item, you want the mouse to ignore the ghost preview itself. If you don't set the mouse's TargetFilter to the preview model, the Raycast will hit the item the player is holding, causing it to glitch out and jump toward the camera. It's a tiny detail, but it's the difference between a broken script and a smooth experience.
Building a system like this is a bit of a rite of passage for Roblox devs. It's frustrating at first, especially when CFrames start acting weird, but seeing it all come together is incredibly rewarding. Just take it one step at a time—start with the mouse position, move to the grid, and worry about the collisions last. You'll have a working system before you know it.