If you've been messing around with physics constraints lately, you've probably realized that setting the roblox studio torsion spring stiffness correctly is the difference between a smooth-moving door and a glitchy mess that launches your character across the map. It's one of those settings that seems straightforward until you actually try to make something feel "heavy" or "snappy," and suddenly your parts are vibrating like they've had too much coffee.
Torsion springs are a bit different from your standard spring constraints. While a regular spring deals with linear movement—pushing and pulling in a straight line—the torsion spring is all about rotation. It wants to twist things back to a specific angle. If you're building a saloon door, a catapult, or even a complex car suspension, this is the constraint you're going to be spending a lot of time with.
What does stiffness actually do?
At its core, the stiffness property in a TorsionSpringConstraint determines how much force is applied to bring the parts back to their relative target angle. Think of it like the "strength" of the spring. If you have a very low stiffness, the spring is weak. You can push the part easily, and it'll slowly, lazily drift back to where it started.
On the flip side, if you crank that stiffness up to a high number, the spring becomes incredibly rigid. It'll fight you the moment you try to move it. In Roblox, these values aren't just 1 to 10. You'll often find yourself typing in numbers like 1,000, 10,000, or even millions depending on how heavy the parts are. That's the first thing to keep in mind: the mass of the objects you're connecting matters immensely. A stiffness value that works for a tiny wooden plank will do absolutely nothing for a massive concrete wall.
The balance between stiffness and damping
You really can't talk about roblox studio torsion spring stiffness without mentioning its best friend, damping. If stiffness is the "power" that pulls the spring back, damping is the "brake" that keeps it from overshooting.
Imagine you have a swinging door with high stiffness but zero damping. You push the door, and the spring slams it back toward the center. But because there's nothing to slow it down, the door flies past the center point, swings out the other side, and keeps oscillating forever. It looks ridiculous.
To get that "premium" feel in your game, you have to find the sweet spot between these two. Usually, I start by setting my stiffness until the object moves at the speed I want, and then I slowly increase the damping until the bouncing stops. A good rule of thumb is that if your object is jittering or vibrating violently, your stiffness is likely too high for the amount of mass it's moving, or your damping is too low to settle the energy.
Why mass changes everything
One of the most common frustrations I see people having in Roblox Studio is when they copy settings from one project to another and it just doesn't work. The culprit is almost always the Part's mass.
Roblox physics are based on real-world concepts (mostly), so torque is a big deal here. If you have a long, heavy arm attached to a torsion spring, that arm has a lot of rotational inertia. A stiffness value of 5000 might not even be enough to lift it against gravity. But if you take that same 5000 stiffness and apply it to a small 1x1x1 stud cube, that cube is going to snap back so fast it might break the physics solver.
If you're struggling to get a heavy object to move, don't be afraid to go into the millions for stiffness. Just remember to bump the damping up accordingly. Also, check if your parts are "Massless." If you check that box in the properties, the torsion spring will have a much easier time, but it might also feel a bit "floaty."
Practical uses for torsion springs
There are a few classic scenarios where you'll definitely be tweaking these values.
Swinging Doors
This is the most common use case. You want a door that players can walk through, but it should swing shut behind them. For this, you want a relatively low stiffness. You want the player to feel like they are pushing something, not hitting a wall. A bit of damping is crucial here so the door doesn't flap back and forth for a minute after someone walks through.
Vehicle Suspension
If you're building a custom chassis, torsion springs are great for A-arms or trailing arm suspensions. Here, the roblox studio torsion spring stiffness needs to be high enough to support the weight of the car without bottoming out, but low enough that the wheels can actually move up and down over bumps. It's a delicate dance.
Melee Weapons and "Floppy" Physics
Sometimes you want a bit of "weight" to a weapon. If you attach a morning star or a flail using a torsion spring instead of a basic hinge, you can make the head of the weapon feel like it's resisting the swing and then snapping forward. It adds a layer of juice to the animation that procedural physics handles better than a canned animation ever could.
Dealing with the "Jitter"
We've all been there. You hit Play, and your object starts shaking like it's about to explode. This usually happens when the physics engine is trying to solve a conflict that it can't mathematically handle.
If your roblox studio torsion spring stiffness is set to an astronomical number, the engine tries to move the part back to the target angle in a single frame. But in doing so, it overshoots just a tiny bit. The next frame, it tries to correct that overshoot with massive force, overshooting again in the opposite direction. Boom—you have a jittery part.
To fix this, try these steps: 1. Lower the stiffness. Do you really need it that high? 2. Increase the mass of the parts. Heavier parts are harder to "flick" around, which can stabilize the simulation. 3. Check your MaxTorque. By default, this is usually set to a huge number. Sometimes limiting the torque can prevent the spring from applying "infinite" force and breaking things. 4. Turn on Adaptive Timestepping. In your Workspace settings, changing the physics stepping to Adaptive can sometimes help the engine handle complex constraints better, though it's not a magic fix for bad settings.
Scripting your springs
Don't forget that you can change these properties on the fly. I've found that dynamically adjusting stiffness can create some really cool effects. For example, if you have a mechanical bridge, you might want the stiffness to be low while it's moving so it looks smooth, but then crank the stiffness (and damping) way up once it's in place to "lock" it so players can walk over it without it sagging.
lua -- A quick example of hardening a spring local spring = script.Parent.TorsionSpringConstraint spring.Stiffness = 1000000 -- Lock it down spring.Damping = 500
It's a simple change, but it opens up a lot of possibilities for interactive environments.
Final thoughts on tuning
The best way to master roblox studio torsion spring stiffness is honestly just through trial and error. Open a empty baseplate, throw down two parts, connect them with a hinge and a torsion spring, and just start typing in numbers.
Watch how the parts react. See what happens when you double the stiffness. See what happens when you set the damping to zero. Once you get a "feel" for the numbers, you won't have to guess as much when you're working on a real project. Just remember: mass matters, damping is your friend, and if it starts vibrating, you've probably gone too far.
Roblox's physics engine is surprisingly powerful, and the torsion spring is one of the best tools for making your world feel less like a collection of static blocks and more like a living, breathing mechanical space. Keep tweaking those values, and you'll get that perfect "snap" eventually.