Slider Joint 2D

This joint allows a game object controlled by rigidbody physics to slide along a line in space, like sliding doors, for example. The object can freely move anywhere along the line in response to collisions or forces or, alternatively, it can be moved along by a motor force, with limits applied to keep its position within a certain section of the line.

Details

(See also Joints 2D: Details and Hints for useful background information on all 2D joints.)

Use this joint to make objects slide! The aim of this joint is to maintain the position of two points on a configurable line that extends to infinity. Those two points can be two Rigidbody2D components or a Rigidbody2D component and a fixed position in the world. (Connect to a fixed position in the world by setting Connected Rigidbody to None).

The joint applies a linear force to both connected rigid body objects to keep them on the line. It also has a simulated linear motor that applies linear force to move the ridid body objects along the line. You can turn the motor off or on. Athough the line is infinite, you can specify just a segment of the line that you want to use, using the Translation Limits option.

This joint has three simultaneous constraints. All are optional:

• Maintain a relative linear distance away from a specified line between two anchor points on two rigid body objects.
• Maintain a linear speed between two anchor points on two rigid body objects along a specified line. (The speed is limited with a maximum force.)
• Maintain a linear distance between two points along the specified line.

For Example:

You can use this joint to construct physical objects that need to react as if they are connected together on a line. Such as:

• A platform which can move up or down. The platform reacts by moving down when something lands on it but must never move sideways. You can use this joint to ensure platform to never moves up or down beyond certain limits. Use the motor to make the platform move up.