rojo/.cursor/rules/roblox/en-us/physics/constraints/universal.md

title	description
Universal	UniversalConstraint ensures two axes on two assemblies remain perpendicular, useful for applications such as vehicle power transmission to rear drive shafts, robotics, and more.

For an overview on creating, visualizing, and simulating mechanical constraints, including `Class.UniversalConstraint`, see [Mechanical constraints](../../physics/mechanical-constraints.md). Also see [Roblox units](../../physics/units.md) to understand how Roblox units compare to metric units.

A Class.UniversalConstraint ensures two axes on two assemblies remain perpendicular. Example applications include vehicle power transmission to the rear drive shafts, robotics, and more.

Orientations

Orientation of a universal's two attachments affects how it will move. To ensure it behaves correctly, the Class.Attachment.SecondaryAxis|SecondaryAxis of the attachments, visualized by the orange arrows, should be perpendicular to each other. Note that a green L-shaped indicator appears when the axes are properly oriented.

Limits

Enabling the Class.UniversalConstraint.LimitsEnabled|LimitsEnabled property exposes the Class.UniversalConstraint.MaxAngle|MaxAngle limit to restrict tilt within a cone, as well as Class.UniversalConstraint.Restitution|Restitution which defines the elasticity of the attachments when they reach the limit.