Physics.Raycast

Parameters

Returns

bool 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.

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

#pragma strict
function FixedUpdate() {
	var fwd: Vector3 = transform.TransformDirection(Vector3.forward);
	if (Physics.Raycast(transform.position, fwd, 10))
		print("There is something in front of the object!");
}

using UnityEngine;

public class ExampleClass : MonoBehaviour 
{
    void FixedUpdate() 
    {
        Vector3 fwd = transform.TransformDirection(Vector3.forward);

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

Notes: Raycasts will not detect Colliders for which the Raycast origin is inside the Collider.

If you move Colliders from scripting or by animation, you need to allow at least one FixedUpdate to be executed so that the physics library can update before a Raycast will hit the Collider at its new position.

Parameters

Returns

bool 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
{
    public Missile missile;

    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
{
    public Missile missile;

    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 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 
{
    void Update() 
    {
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        if (Physics.Raycast(ray, 100)) 
            print("Hit something!");
    }
}

Parameters

Returns

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

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