⚙️ Roblox Physics Constraints Explained – Hinges, Springs, and More

Physics constraints are one of the most powerful — and often misunderstood — features in Roblox Studio. They allow you to create realistic mechanical systems, vehicles, moving doors, suspension systems, and more, all without complex scripting.

In this guide, we’ll break down exactly how Roblox physics constraints work in 2025, how to set them up, and common mistakes to avoid.

What Are Physics Constraints?

In Roblox, constraints are special objects that connect two parts (or a part to the world) and apply specific physical rules to their movement. Instead of manually scripting movement, constraints handle the motion for you — powered by Roblox’s physics engine.

Popular Uses:

• Vehicle steering and suspension

• Rotating doors and windmills

• Elevators and pulleys

• Bouncing platforms and trampolines

• Chain swings and cranes

Types of Physics Constraints

1. HingeConstraint – Rotational Joints

The HingeConstraint lets one part rotate around a single axis, just like a door hinge or car wheel.

Example: A medieval trebuchet arm rotating to launch a projectile.

Key Properties:

• MotorMaxTorque – Strength of rotation force

• MotorSpeed – Speed of rotation

• LimitsEnabled – Restrict rotation angles

Pro Tip: Use with an Attachment on both parts for precise axis control.

2. SpringConstraint – Elastic Motion

The SpringConstraint connects two parts with an invisible spring. It pulls them together or pushes them apart based on a rest length.

Example: Vehicle suspension or bouncy bridges.

Key Properties:

• FreeLength – Rest length of the spring

• Stiffness – How strong the spring’s pull/push is

• Damping – How much the motion slows down over time

Pro Tip: High stiffness with low damping creates a strong bounce; low stiffness with high damping creates smooth suspension.

3. RodConstraint – Fixed Distance Connector

Keeps two parts at a set distance apart, useful for cranes or moving platforms.

4. BallSocketConstraint – Full Rotation Freedom

Lets two parts rotate freely in all directions around the connection point.

Example: Human-like joints, swinging ropes.

5. PrismaticConstraint – Sliding Motion

Allows one part to slide along a straight path relative to another part.

Example: Elevator platforms, retractable bridges.

6. CylindricalConstraint – Rotate + Slide

Combines rotation and sliding along the same axis.

Example: Drills, telescopic poles.

How to Set Up a Constraint

1. Insert Two Parts you want to connect.

2. Add Attachments in the exact position you want the constraint to connect.

3. Insert the Constraint into one of the parts.

4. Assign Attachment0 and Attachment1 to the two attachments.

5. Adjust Properties to fit your desired motion.

   
   

Common Mistakes to Avoid

• ❌ Forgetting attachments — constraints won’t work without them.

• ❌ Misaligned attachments — causes weird rotations or offset movement.

• ❌ Overusing constraints — too many can slow performance.

  
  

Advanced Tips

• Use AlignOrientation and AlignPosition constraints for smooth motion in combination with physical constraints.

• Combine multiple constraints (e.g., Hinge + Spring) for complex behaviors.

• Experiment with ActuatorType in hinges to switch between Servo, Motor, and none.

Conclusion | Roblox Physics Constraints

Roblox physics constraints give you the power to create realistic, interactive mechanics without writing thousands of lines of code.

By mastering hinges, springs, and other constraints, you can build vehicles, machines, and dynamic environments that feel alive.

(Roblox Physics Constraints)