Detect contact between 2D Physics Core objects

To detect contact between 2D Physics Core objects, use either of the following approaches:

• Detect a contact event or trigger event.
• Check whether 2D physics objects overlap or will collide, also known as intersections. For more information, refer to PhysicsQuery.

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 instead.

Detect contact

To detect when objects make contact, enable Unity reporting collision events or trigger events. Follow these steps:

1. Create a GameObject with a script that implements the PhysicsAreaCallbacks.IContactCallback or PhysicsAreaCallbacks.ITriggerCallback interface, and a callback method. For example:

   public class DetectCollisions : MonoBehaviour, PhysicsAreaCallbacks.IContactCallback
   {
       public void OnContactBegin2D(PhysicsAreaCallbacks.ContactBeginEvent beginEvent)
       {
           Debug.Log("Contact started between areas: " + beginEvent.areaA + " and " + beginEvent.areaB);
       }
   }
   

   For more information, refer to PhysicsAreaCallbacks.ContactBeginEvent.

2. Select the GameObject you want to detect contact for.

3. In the Inspector window, expand the Definition section of the Physics Area component.

4. Enable Contact Events or Trigger Events.

5. In the Callbacks section, set Callback Source to Area.

6. Set Callback Target to the GameObject with the script you created in step 1.

If two areas that have either property enabled make contact, they both report the event to Unity.

To run a method or set a parameter you select in the Inspector window instead, set Callback Source to Events and use the properties in the Event settings section.

Additional resources

• Introduction to collision in 2D Physics Core
• Configure collisions between 2D Physics Core objects
• Physics Pose component reference
• Configure global 2D Physics Core settings