Obbys

Building Obbys in Roblox Studio: What Actually Works

Most people who come into obbys build them by just stacking platforms and calling it done. That's why half the obbys out there are unplayable. The difference between one that gets plays and one that sits at zero is actually pretty straightforward once you've made enough of them to break them all.

I've been building these since 2017, before they hit their current wave of popularity, and the core mechanics haven't changed much. What has changed is the expectations. Players now expect smooth checkpoint systems, readable difficulty curves, and at least functional jumping mechanics. Let me walk through what I actually use when building.

Starting the Obbys Project

Create a new Experience in Roblox Studio. I default to a Baseplate template and then immediately delete everything except the terrain. You'll need a Part for each platform, and I always use AssemblyLinearVelocity for any moving platforms rather than TweenService on the part itself. The difference in perceived smoothness is night and day because tweening interpolates position but the physics engine doesn't care, and players will feel that stutter.

Set your workspace gravity to 196.2 if you want that tighter, snappier feel. Default Roblox gravity at 196.0 is fine, but almost every popular obby tweaks this slightly. It's a small detail players won't articulate but will notice.

Checkpoint Systems That Don't Break

Here's where most builders mess up. The classic approach uses a touch event on each checkpoint part that saves the player's respawn location to a Dictionary in a ServerScriptService module. It works until two players hit the same checkpoint at the same frame, and then you get race conditions where Player A respawns at Checkpoint 5 but the Dictionary was just overwritten by Player B at Checkpoint 3.

The fix is per-player checkpoint tracking using the player's UserId as the key. My implementation looks like this:

local checkpointData = {}

game.Players.PlayerAdded:Connect(function(player)
    checkpointData[player.UserId] = {x = 0, y = 10, z = 0}
end)

-- On checkpoint touch
local function onCheckpointTouch(otherPart, checkpoint)
    local character = otherPart.Parent
    local player = game.Players:GetPlayerFromCharacter(character)
    if not player then return end
    
    checkpointData[player.UserId] = {
        x = checkpoint.Position.X,
        y = checkpoint.Position.Y,
        z = checkpoint.Position.Z
    }
end

Respawn logic reads from that same table. It's simple but it prevents the most common bug where players die at a later checkpoint and respawn at an earlier one because someone else triggered it first.

Difficulty Curves

A well-structured obby should have three distinct phases. The first phase is tutorial space where the jumps are generous and the spacing is wide. Players learn the mechanics without failing. The second phase ramps up. Jumps get tighter, moving platforms appear, and the consequences for missing increase. The third phase is where the harder stuff lives, and you should front-load the easy sections here so players who make it this far feel like they earned it.

I usually aim for roughly a 70-20-10 split across these phases. Something like 70% of the course in phase one and two combined, 20% hitting the harder territory, and the remaining 10% being genuinely difficult sections that separate the casual players from the ones who'll actually finish it. If your hardest section comes too early, people quit before they ever experience the full course. If it comes too late, players forget why they're pushing through. I use a simple cycle pattern for moving platforms. Go right for two seconds, pause half a second, return to origin for two seconds, pause another half second. That gives players time to react and also time to recover if they miss. If you remove the pause, the platform becomes effectively chaotic because there's no stable state to orient yourself around. The exact numbers I use are:

• Movement duration: 1.5 to 2.5 seconds depending on distance
• Pause duration: 0.3 to 0.5 seconds
• Speed: calculated so the platform covers the distance within the movement window

The "One Section Will Break" Problem

I spent three weeks on a particular jump sequence in one of my builds. Six consecutive platforms with decreasing size and increasing gap distance. Every single one of those platforms was individually tested by jumping from every angle. Still, a player found a path where if you sprint-jumped off the third platform at exactly the right frame, you could clip through the invisible wall near the edge and fall into void space.

The workaround was adding an upward-facing invisible brick at that junction with CanCollide set to false but positioned to prevent the clip path. It's ugly and nobody will ever know it's there, but it solved the issue. Test every corner case you can think of, and then test the cases you can't. Here's a lightweight version:

local VOID_THRESHOLD = -200

game.Workspace.DescendantAdded:Connect(function(child)
    if child:IsA("HumanoidRootPart") and child.Position.Y VOID_THRESHOLD then
        local player = game.Players:GetPlayerFromCharacter(child.Parent)
        if player and checkpointData[player.UserId] then
            local cp = checkpointData[player.UserId]
            child.Position = Vector3.new(cp.x, cp.y + 5, cp.z)
            player.Character.HumanoidRootPart.Velocity = Vector3.new(0, 0, 0)
        end
    end
end)

Scaling for Performance

An obby with 200+ parts will start showing frame drops on lower-end devices if you're not careful. The main culprits are: unoptimized mesh parts (use Block for everything possible), excessive weld constraints between moving parts, and render-stepped updates that run every frame on every platform.

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I consolidate where I can. If you have a sequence of static platforms forming a bridge, merge them into a single Part rather than welding ten Blocks together. One part means one render call instead of ten. For moving sequences that need to stay modular, use a single Part and animate its position, not a chain of welded pieces. The result is usually a 30-40% improvement in frame times on mid-range devices. That's the difference between an obby that plays smoothly and one that loses players in the first thirty seconds.

Common Pitfalls

The biggest one is underestimating how hard a jump feels in first-person. A gap that looks generous from above might be nearly impossible when you're looking straight ahead at it. Always test from the player's actual perspective, not the builder's god view.

Another one is checkpoint placement. Don't put a checkpoint immediately before an extremely difficult section. That gives players a false sense of security, and when they fail the section right after, they've lost all progress. Place checkpoints at natural resting points where the difficulty transitions, not right before the wall. Lastly, music and sound matter more than most builders think. A well-timed jump sound on successful completion of a difficult section releases tension. A failure sound that's too harsh makes people want to quit. Keep death sounds subtle and reward sounds satisfying.

Summary of Practical Setup

Start with a baseplate, disable default terrain features you don't need, set up per-player checkpoint storage early, build in phases with a 70-20-10 difficulty split, use predictable movement cycles for platforms, merge static geometry whenever possible, and test every section from the player's actual camera angle. That's the framework I go back to every time, and it's cut my build time down from what used to be days per course to something more like hours.