# Add a constraint

> Connect two 2D Physics Core objects with a Physics Constraint component.

To connect two 2D Physics Core objects, add a Physics Constraint component to one of them, and assign the other as the object it connects to.

> **Note:**
>
> This documentation is about using Pose, Area, and Constraint components. To use 2D physics in the Unity Editor using components like the Rigidbody 2D component, refer to [2D physics](/engine/6000.7/manual/unity2d/2d-physics.md.md) instead.

Follow these steps:

1. Select a GameObject with a Physics Pose component.

2. In the Editor window, select **Add Component**.

3. Select **Physics 2D (Core)**, then select a constraint component, for example **Physics Constraint Distance**.

   Unity connects one end of the constraint to this GameObject, by setting **Pose A Source** to the Physics Pose component. To connect a different GameObject instead, set **Pose A Source** to **Custom**.

4. Expand the **Pose** section, then drag the second GameObject you want to connect to the **Pose B Target** property, or select the picker (**⊙**).

For the full list of Physics Constraint components and what each one does, refer to [Introduction to constraints](/engine/6000.7/manual/unity2d/2d-physics-api/connect-objects/joints.md).

## Configure springiness

> **Note:**
>
> Some constraints don't have a spring.

To make the constraint act like a spring, follow these steps:

1. In the **Inspector** window, expand the **Definition** section, then expand **Spring**.
2. Enable **Enable Spring**.
3. Set **Spring Frequency** to a value greater than 0. A lower value makes the spring stiffer.
4. Set **Spring Damping** to a value greater than 0. A higher value makes the spring settle more quickly.

## Add a motor

> **Note:**
>
> Some constraints don't have a motor.

To make the constraint act like a winch that pulls or pushes the connected objects, follow these steps:

1. In the **Inspector** window, expand the **Definition** section, then expand **Motor**.
2. Enable **Enable Motor**.
3. Set **Motor Speed** to a value greater than 0 to make the motor push the connected objects apart, or less than 0 to make the motor pull the connected objects together.
4. Set **Max Motor Force** or **Max Motor Torque** to a value greater than 0. These properties set the maximum force that the motor applies to reach the **Motor Speed**.

## Share constraint properties

To share the same properties across multiple constraints, create a definition asset. For more information, refer to [Share properties across multiple 2D Physics Core components](/engine/6000.7/manual/unity2d/2d-physics-api/properties/definitions.md).

To also allow the shapes on the two connected objects to collide with each other, enable **Collide Connected** in the **Definition** section of the constraint component.

## Additional resources

* [Introduction to constraints](/engine/6000.7/manual/unity2d/2d-physics-api/connect-objects/joints.md)
* [Detect constraint events](/engine/6000.7/manual/unity2d/2d-physics-api/connect-objects/constraint-events.md)
* [Share properties across multiple 2D Physics Core components](/engine/6000.7/manual/unity2d/2d-physics-api/properties/definitions.md)
* [Connecting 2D Physics Core objects](/engine/6000.7/manual/unity2d/2d-physics-api/connect-objects.md)