A roblox custom pet ai script is essentially the heartbeat of any successful simulator or adventure game on the platform. It's one thing to have a high-poly, adorable dragon model sitting in your inventory, but it's a completely different challenge to make that dragon feel alive. If you've ever played a game like Pet Simulator 99 or Adopt Me, you know that the "feel" of the pet—how it follows you, how it avoids bumping into walls, and how it idles when you stop—is what makes the experience immersive rather than just a collection of moving parts.
Getting your pet to behave correctly involves a mix of physics, pathfinding, and a little bit of creative math. You aren't just telling a part to "go to the player"; you're telling it how to navigate a 3D space in a way that doesn't look janky or mechanical.
Why a Custom Script Beats the Basic Follow Logic
You might be tempted to just use a simple MoveTo command or a basic "while true" loop that sets the pet's position to the player's position. Please, don't do that. It looks stiff, the pet will likely clip through the floor, and it will definitely lag your game once you have more than five players on a server.
A real roblox custom pet ai script handles things like "lerping" (Linear Interpolation) for smooth movement, or better yet, utilizes Roblox's newer physics constraints like AlignPosition and AlignOrientation. These tools allow the pet to move smoothly through the world using the engine's built-in physics, which means they'll react naturally to gravity and collisions without you having to write a thousand lines of manual positioning code.
The Foundation: Setting Up Your Pet Model
Before you even touch a script, your pet model needs to be set up for success. Usually, this means having a "PrimaryPart" (often an invisible box called the RootPart) that encompasses the whole pet.
- Rigging: Make sure your pet is properly rigged if you want it to have animations like walking or tail-wagging.
- Collisions: You'll likely want to turn off collisions for the pet itself (
CanCollide = false) so it doesn't accidentally shove the player off a cliff when it gets too close. - Attachments: If you're using physics constraints, you'll need attachments in both the pet's RootPart and the player's Character (usually the HumanoidRootPart).
Once the physical structure is solid, the script has a much easier job.
Breaking Down the AI Logic
When you're writing a roblox custom pet ai script, you're basically managing a state machine. The pet needs to know what it's doing at all times. Is it following the player? Is it idling? Is it performing a trick?
The Follow State
The most common state is the "Follow." You don't want the pet to be exactly where the player is—that's just messy. Instead, you calculate an offset. Maybe the pet stays two studs to the left and three studs behind. Using CFrame, you can calculate this "goal" position every frame or every physics step.
A common trick is using RunService.Heartbeat. This runs every single frame after the physics have been calculated. Inside this loop, your script checks the distance between the pet and the player. If the distance is greater than, say, 10 studs, the pet starts moving toward the goal. If it's within 5 studs, it can slow down or stop.
Handling Obstacles with Pathfinding
If your game has a lot of walls, trees, or houses, a simple "move toward player" script will result in your pet getting stuck behind a mailbox for the entire game. This is where PathfindingService comes in.
A sophisticated roblox custom pet ai script will check if there's a direct line of sight between the pet and the player. If there is, it moves directly. If a wall is in the way, the script triggers a pathfinding request to calculate a series of waypoints around the obstacle. It adds a level of polish that separates amateur games from front-page hits.
Physics vs. Tweening: Which is Better?
There's a big debate in the Roblox dev community about whether to move pets using physics or TweenService.
Tweening is incredibly smooth and easy to predict. It's great for floating pets (like a hovering ghost or a robot). However, tweens don't care about physics. A tweened pet will fly through a wall if you tell it to go from point A to point B.
Physics-based movement (using LinearVelocity or AlignPosition) is much more "Roblox-y." The pet will bump into things, tumble if it hits a curb too fast, and generally feel like it exists in the world. For walking pets, physics is almost always the way to go because it handles the floor height automatically. You don't want your pet hovering six inches off the ground or sinking into the grass.
Adding Personality with Idle Behaviors
The "AI" part of a roblox custom pet ai script really shines when the player isn't moving. If the player goes AFK to check their inventory, what does the pet do?
You can script "flavors" of behavior: * The Energetic Pet: It might run circles around the player or do occasional backflips. * The Lazy Pet: It might sit down or play a "yawn" animation after five seconds of inactivity. * The Distracted Pet: It could sniff a nearby part or look at other players passing by.
These small additions don't take much code—usually just a random number generator and a few if statements—but they make the custom pet feel like a character rather than a 3D mesh glued to the player's backside.
Optimization: Don't Kill the Server
This is the part where many beginners trip up. If you have 20 players and each has 3 pets, that's 60 AI scripts running simultaneously. If those scripts are all handled by the server, your game's ping is going to skyrocket.
To optimize your roblox custom pet ai script, you should handle the visual movement on the Client (LocalScript). The server should know where the pet is for data purposes, but the actual "smooth moving" should happen on each player's computer. This makes the movement look buttery smooth for the player and takes the heavy lifting off the server's shoulders.
Another trick is to lower the update frequency for pets that are far away. If a pet is 200 studs away from your camera, do you really need to calculate its tail wagging 60 times a second? Probably not.
Troubleshooting Common Jitters
If your pet is "stuttering" or vibrating wildly, it's usually one of two things: 1. Network Ownership: The server and the client are fighting over who controls the pet's position. Make sure to set the pet's network owner to the player it belongs to using part:SetNetworkOwner(player). 2. Conflicting Forces: If you're using an AlignPosition but the pet is too heavy, the force might not be enough to move it, causing it to jerk. Or, if the MaxForce is infinite, it might snap so hard it glitches through the map.
The Wrap-Up
Building a roblox custom pet ai script is a rite of passage for many Roblox developers. It forces you to learn about vectors, CFrames, physics, and client-server communication. It's a bit frustrating at first—you'll definitely deal with pets flying off into the stratosphere or getting stuck under the baseplate—but once you get that smooth, responsive movement, it changes the entire vibe of your game.
Start simple. Get a cube to follow you. Then, make it stop a few studs away. Then, add a "jump" if the player jumps. Before you know it, you'll have a pet system that feels as professional as anything on the platform. Just remember to keep your code clean, keep your physics in check, and always test with more than one pet to see how the lag holds up!