Physics.Raycast

Parameters

Returns

bool Returns true if the ray intersects with a Collider, otherwise false.

Description

Casts a ray, from point origin, in direction direction, of length maxDistance, against all colliders in the Scene.

To select which layers a ray should collide with, use a LayerMask.

Specifying queryTriggerInteraction allows you to control whether or not Trigger colliders generate a hit, or whether to use the global Physics.queriesHitTriggers setting.

Notes: Raycasts will not detect Colliders for which the Raycast origin is inside the Collider. In all these examples M:UnityEngine.MonoBehaviour.FixedUpdate is used rather than M:UnityEngine.MonoBehaviour.Update. Refer to Order of execution for event functions to understand the difference between M:UnityEngine.MonoBehaviour.Update and M:UnityEngine.MonoBehaviour.FixedUpdate, and to see how they relate to physics queries.

This example creates a simple Raycast, projecting forwards from the position of the object's current position, extending for 10 units.

using UnityEngine;

public class ExampleClass : MonoBehaviour
{
    LayerMask layerMask;

    void Awake()
    {
        layerMask = LayerMask.GetMask("Wall", "Character");
    }

    // See Order of Execution for Event Functions for information on FixedUpdate() and Update() related to physics queries
    void FixedUpdate()
    {

        RaycastHit hit;
        // Does the ray intersect any objects excluding the player layer
        if (Physics.Raycast(transform.position, transform.TransformDirection(Vector3.forward), out hit, Mathf.Infinity, layerMask))

        {
            Debug.DrawRay(transform.position, transform.TransformDirection(Vector3.forward) * hit.distance, Color.yellow);
            Debug.Log("Did Hit");
        }
        else
        {
            Debug.DrawRay(transform.position, transform.TransformDirection(Vector3.forward) * 1000, Color.white);
            Debug.Log("Did not Hit");
        }

    }
}

using UnityEngine;

public class ExampleClass : MonoBehaviour
{
    // See Order of Execution for Event Functions for information on FixedUpdate() and Update() related to physics queries
    void FixedUpdate()
    {
        Vector3 fwd = transform.TransformDirection(Vector3.forward);

        if (Physics.Raycast(transform.position, fwd, 10))
            print("There is something in front of the object!");
    }
}

Parameters

Returns

bool Returns true when the ray intersects any collider, otherwise false.

Description

Casts a ray against all colliders in the Scene and returns detailed information on what was hit.

This example reports the distance between the current object and the reported Collider:

This example re-introduces the maxDistance parameter to limit how far ahead to cast the Ray:


Additional resources: RaycastHit

using UnityEngine;

public class RaycastExample : MonoBehaviour
{
    // See Order of Execution for Event Functions for information on FixedUpdate() and Update() related to physics queries
    void FixedUpdate()
    {
        RaycastHit hit;

        if (Physics.Raycast(transform.position, -Vector3.up, out hit))
            print("Found an object - distance: " + hit.distance);
    }
}

using UnityEngine;

public class RaycastExample : MonoBehaviour
{
    // See Order of Execution for Event Functions for information on FixedUpdate() and Update() related to physics queries
    void FixedUpdate()
    {
        RaycastHit hit;

        if (Physics.Raycast(transform.position, -Vector3.up, out hit, 100.0f))
            print("Found an object - distance: " + hit.distance);
    }
}

Parameters

Returns

bool Returns true when the ray intersects any collider, otherwise false.

Description

Same as above using ray.origin and ray.direction instead of origin and direction.

using UnityEngine;
using UnityEngine.InputSystem;
                        
public class ExampleClass : MonoBehaviour
{
    // See Order of Execution for Event Functions for information on FixedUpdate() and Update() related to physics queries
    void FixedUpdate()
    {
        Ray ray = Camera.main.ScreenPointToRay(Mouse.current.position.ReadValue());
        if (Physics.Raycast(ray, 100))
            print("Hit something!");
    }
}

Parameters

Returns

bool Returns true when the ray intersects any collider, otherwise false.

Description

Same as above using ray.origin and ray.direction instead of origin and direction.

This example draws a line along the length of the Ray whenever a collision is detected:

Additional resources: RaycastHit

using UnityEngine;
using UnityEngine.InputSystem;
                        
public class ExampleClass : MonoBehaviour
{
    // See Order of Execution for Event Functions for information on FixedUpdate() and Update() related to physics queries
    void FixedUpdate()
    {
        Ray ray = Camera.main.ScreenPointToRay(Mouse.current.position.ReadValue());
        RaycastHit hit;

        if (Physics.Raycast(ray, out hit, 100))
            Debug.DrawLine(ray.origin, hit.point);
    }
}