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.

You may optionally provide a LayerMask, to filter out any Colliders you aren't interested in generating collisions with.

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 FixedUpdate is used rather than Update. Please see Order of Execution for Event Functions to understand the difference between Update and FixedUpdate, and to see how they relate to physics queries.

using UnityEngine;

// C# example.

public class ExampleClass : MonoBehaviour
{
    // See Order of Execution for Event Functions for information on FixedUpdate() and Update() related to physics queries
    void FixedUpdate()
    {
        // Bit shift the index of the layer (8) to get a bit mask
        int layerMask = 1 << 8;

        // This would cast rays only against colliders in layer 8.
        // But instead we want to collide against everything except layer 8. The ~ operator does this, it inverts a bitmask.
        layerMask = ~layerMask;

        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");
        }
    }
}

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
{
    // 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:

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);
    }
}

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

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;

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(Input.mousePosition);
        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:

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()
    {
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        RaycastHit hit;

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