Getting a working roblox portal clone script into your project is one of those things that sounds way easier than it actually is. We've all seen the classic Valve game, and we've all thought, "Man, I could totally build that in Luau." Then you actually sit down to do it and realize that calculating relative momentum and handling recursive camera views is a bit of a headache. But honestly, it's one of the most rewarding mechanics you can add to a game because it completely changes how players interact with your world.
If you're trying to build one, you're probably looking for that seamless transition where a player walks into a blue oval and pops out of an orange one without a hitch. It's not just about teleporting a character from point A to point B; it's about making it feel smooth. If there's a stutter or the player ends up facing the wrong direction, the magic is instantly broken.
Why the logic is harder than it looks
The core of any roblox portal clone script is the math behind CFrames. If you aren't familiar with CFrames, they're basically the way Roblox handles position and rotation all in one go. To make a portal work, you can't just set the player's position to the other portal. You have to calculate their offset from the first portal and then apply that same offset, mirrored or rotated, to the second one.
Think about it this way: if you walk into the left side of Portal A, you should come out of the right side of Portal B. If you're running at a 45-degree angle into the wall, you should maintain that angle when you exit. Most beginner scripts forget this, and the player just "snaps" to the center of the exit portal. It feels clunky and amateur. To get it right, you're going to be doing a lot of ToLocalSpace and ToWorldSpace calculations. It sounds intimidating, but once you wrap your head around relative coordinates, it starts to click.
Handling the momentum problem
One of the coolest things about portals is the "speedy thing goes in, speedy thing comes out" rule. If you're making a roblox portal clone script, you have to account for the player's velocity. Roblox physics can be a bit finicky when you suddenly change an object's position.
When a player hits the portal's trigger part, you need to grab their current AssemblyLinearVelocity. Then, you have to rotate that velocity vector so it matches the orientation of the exit portal. If you don't do this, the player might run into a portal on the floor and just stop. Or worse, they'll keep their downward momentum and get slammed into the ground the moment they exit a wall portal. You want them to go flying out with all that energy they had going in. It's what makes those long-distance jump puzzles possible.
What about the visuals?
Let's be real: a portal that's just a flat, colored part is kind of boring. You want to see through it. This is where things get tricky on Roblox. Since we don't have true "portal rendering" built into the engine like some high-end custom engines do, we have to get creative.
Most developers use ViewportFrames to create the illusion of looking through the portal. Basically, you're rendering a second "miniature" version of the world inside a UI element on the portal's surface. It's a bit of a performance hog if you aren't careful. If you have ten portals all rendering ViewportFrames at once, your players' frame rates are going to tank faster than a lead brick.
The trick is only updating the ViewportFrame when the player is actually looking at it. You can use some simple dot product math to check if the player's camera is facing the portal. If they're looking away, just turn off the update loop. Their GPU will thank you.
Scripting the teleportation trigger
The actual trigger for your roblox portal clone script is usually a Touched event or, if you want to be more precise, a Raycast or a GetPartBoundsInBox check. Touched is okay for simple stuff, but it can be unreliable. Sometimes it fires too late, and the player's character has already clipped through the portal frame and hit the wall behind it.
A better way is to run a fast loop (like RunService.Heartbeat) that checks the player's distance from the portal plane. Once they cross that threshold, you trigger the CFrame swap. This ensures that the transition happens exactly when they hit the surface, not a few milliseconds later when the physics engine finally decides to register a touch.
Dealing with the "Wall Clip" issue
We've all been there—you go through a portal and for a split second, you see the inside of the map or some ugly "void" textures. This happens because the camera is usually a bit behind the player's head. When the player teleports, the camera might still be on the "old" side of the wall for a frame.
To fix this in your roblox portal clone script, you might need to manually offset the camera or use a fade-to-black transition if you can't get it perfectly seamless. But if you're aiming for that high-quality feel, try adjusting the CameraMinZoomDistance or briefly moving the camera's CFrame yourself during the same frame as the teleport. It's all about timing. If the teleport and the camera move happen in the exact same RenderStepped frame, the player won't see a thing.
Optimization and Lag
If you're planning on having your game be multiplayer, oh boy, get ready. Portals in a local environment are one thing, but syncing them across the server is a whole different beast. If the server handles the teleportation, there's going to be a delay based on the player's ping. They'll walk into the portal, keep walking for a second, and then suddenly snap back to the exit. It looks terrible.
The best way to handle this in a roblox portal clone script is to do the teleportation on the client side first. Let the player's own computer move them instantly so it feels responsive. Then, fire a RemoteEvent to tell the server, "Hey, I just went through this portal, update my position for everyone else." You'll need some sanity checks on the server to make sure people aren't using this to cheat and teleport across the map, but for the most part, client-side authority is the way to go for smooth movement.
Where to find a starting point
You don't always have to write every single line from scratch. There are some decent open-source versions of a roblox portal clone script on places like GitHub or the Roblox Developer Forum. Looking at someone else's code is a great way to see how they handled the math. Just be careful with random scripts from the Toolbox. A lot of those are old, unoptimized, or—worst case—contain backdoors that could let someone mess with your game.
If you find a script you like, try to break it. See what happens when you put a portal on the ceiling and one on the floor. See what happens when you throw a physics object through it. If it handles those things without crashing or glitching, you've probably found a winner.
Making it your own
Once you have the basic roblox portal clone script working, start adding your own flair. Maybe your portals change color based on who placed them. Maybe they have a cool particle effect that sucks in nearby debris. Maybe they only work for certain objects or players.
The beauty of Roblox is that once you have that core mechanic down, you can build an entire game around it. Whether it's a puzzle game, a weird obby, or a fast-paced shooter where people are flanking each other through holes in space, the portal logic is the foundation. It's definitely a bit of a steep learning curve if you're new to vector math, but sticking with it is worth it. There's nothing quite like the feeling of finally walking through your own portal and having it work exactly like the "real" thing. Just keep tweaking the CFrames, watch your performance, and you'll get there.