If you're tired of hand-placing parts for hours, using a roblox cellular automata cave script is basically the easiest way to generate organic-looking underground levels in minutes. Honestly, manual building has its place for specific hero assets or tight corridors, but if you want that sprawling, natural feel of a deep cavern, you really need to let an algorithm do the heavy lifting.
Procedural generation might sound like something reserved for math geniuses, but cellular automata is surprisingly approachable. If you've ever seen Conway's Game of Life, you've already seen the logic in action. It's all about a grid of cells that live or die based on who their neighbors are. In the context of Roblox, "living" usually means a stone block exists there, and "dying" means it's empty space for the player to walk through.
Why use cellular automata instead of random noise?
You could just use Perlin noise—which is what Minecraft uses for its terrain—but noise often creates very vertical, floaty structures if you aren't careful with your math. Cellular automata, on the other hand, excels at creating "bubbles" and interconnected rooms. It feels more like an actual cave system because the rules prioritize smoothing out jagged edges.
When you run a roblox cellular automata cave script, it starts with a messy, randomized grid of blocks. It looks like static on an old TV. But then, you run a few "iterations" or "passes." Each pass checks every cell: "How many walls are around me?" If a cell is surrounded by lots of walls, it stays a wall. If it's mostly empty space, it disappears. After four or five rounds of this, that static transforms into smooth, winding tunnels.
Setting up your basic grid
Before you even worry about the "automata" part, you need a way to store your data. Don't start by spawning parts immediately. If you try to create 10,000 parts and then delete them every time the script runs a calculation, your Studio is going to crash faster than a cheap drone.
Instead, you want to store your cave in a 2D or 3D array (basically a table within a table).
```lua local width = 50 local height = 50 local fillChance = 45 -- The percentage of the map that starts as a wall local grid = {}
-- Initialize the grid with random noise for x = 1, width do grid[x] = {} for y = 1, height do if math.random(1, 100) < fillChance then grid[x][y] = 1 -- 1 represents a wall else grid[x][y] = 0 -- 0 represents empty space end end end ```
This snippet just sets the stage. We're telling the script to fill about 45% of our 50x50 area with walls. At this stage, it's just data in a table—no parts have been created in the Workspace yet. This is where the magic happens.
The logic: The 4-5 rule
The industry standard for making decent caves is the "4-5 rule." It's pretty simple: if a wall has fewer than four neighbors that are also walls, it becomes empty space (it "dies"). If an empty space has five or more neighbors that are walls, it becomes a wall (it's "born").
You'll need a function in your roblox cellular automata cave script that counts these neighbors. You check the eight spots around a specific coordinate (top, bottom, left, right, and the four diagonals).
When you run this logic over the whole grid, you can't update the grid as you go. You have to create a new temporary grid for the results of that pass. Why? Because if you change a cell to a wall on the first line, the next cell will see that new wall and change its behavior based on a result that didn't exist at the start of the turn. It gets messy. Always calculate the "next generation" based on the "current generation."
Turning data into actual Roblox parts
Once you've run your smoothing passes—usually about three to five times is the sweet spot—you finally have a table full of 1s and 0s that actually looks like a cave map. Now you need to visualize it.
You can use standard Instance.new("Part"), but if you're making a massive cave, you'll want to look into EditableMesh or at least use BulkMoveTo to keep things performant. If you're going for a more traditional "Roblox" look, simple 4x4x4 blocks work great.
lua for x = 1, width do for y = 1, height do if grid[x][y] == 1 then local wall = Instance.new("Part") wall.Size = Vector3.new(4, 4, 4) wall.Position = Vector3.new(x * 4, 10, y * 4) -- Offset for height wall.Anchored = true wall.Parent = game.Workspace.CaveContainer end end end
Dealing with "Swiss Cheese" syndrome
Sometimes your script will generate a bunch of tiny, isolated pockets that players can't actually reach. It looks like Swiss cheese. To fix this, you can implement a "flood fill" algorithm. Basically, you pick one empty spot in the cave and see how far you can walk from there. Anything the flood fill can't reach is a "dead zone" that you should probably fill back in with stone. This ensures your players don't spawn in a 1x1 closet with no way out.
Making it 3D
The examples above are mostly 2D, which is fine for a top-down game or a side-scroller. But if you want a true 3D cavern you can explore from all angles, you just add a third dimension to your loops. Instead of checking 8 neighbors, you'll be checking 26 neighbors (the 3x3x3 cube surrounding the cell, minus the center).
Fair warning: 3D cellular automata is much more intensive. A 50x50x50 grid is 125,000 cells. If you aren't careful with how you handle that data, your script might hang for a few seconds. To keep it smooth, try breaking the generation up across several frames using task.wait() or only generate the chunks of the cave that are near the player.
Customizing the look and feel
Once you have the basic roblox cellular automata cave script working, you shouldn't just leave it as grey blocks. That's boring. You can use the neighbor count to add variety. For example, if a wall cell has a "0" (empty space) directly below it, that's a ceiling! You can script it to spawn a stalactite model there.
You can also vary the fillChance or the neighbor rules to get different types of caves. A higher fillChance creates tight, claustrophobic tunnels. A lower one creates massive, open cathedral-like spaces. You can even layer different algorithms on top of each other—maybe use cellular automata for the main rooms and then use a "Drunkard's Walk" script to carve out long, thin connector tunnels between them.
Performance considerations
Generating thousands of parts is one of the quickest ways to make a Roblox game laggy. If you're using this script for a large-scale project, I highly recommend using the Smooth Terrain system instead of parts.
Roblox's Terrain API is actually really good for this. Instead of spawning a part, you use workspace.Terrain:FillBlock(). Terrain is much more optimized for large environments, and it handles things like LOD (Level of Detail) automatically, so your players' computers won't catch fire when they enter the cave.
Wrapping things up
Setting up a roblox cellular automata cave script is a bit of a rite of passage for Roblox developers who want to get into procedural generation. It's rewarding because you can see the results immediately. One second you have a chaotic mess of random points, and the next, you have a structured, playable environment that looks like it was designed by hand.
Don't be afraid to mess with the numbers. Change the neighbor requirements, run ten iterations instead of three, or try weird grid sizes. Most of the coolest cave shapes I've found came from accidentally putting a typo in my neighbor check. Just keep an eye on your output console for errors, and remember to clear out your old parts before you run the script a second time!