Physics.Raycast

Parameters

Returns

bool True when the ray intersects any collider, otherwise false.

Description

Casts a ray against all colliders in the scene.

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

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    void Update() {
        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, there needs to be at least one FixedUpdate executed so that the physics library can update its data structures, 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.

var hit : RaycastHit;
if (Physics.Raycast (transform.position, -Vector3.up, hit)) {
	var distanceToGround = hit.distance;
}

RaycastHit hit;
float distanceToGround = 0;

if (Physics.Raycast(transform.position, -Vector3.up, out hit)) {
	distanceToGround = hit.distance;
}

Another example:

// Raycast up to 100 meters down
var hit : RaycastHit;
if (Physics.Raycast (transform.position, -Vector3.up, hit, 100.0)) {
	var distanceToGround = hit.distance;
}

RaycastHit hit;
float distanceToGround = 0;

if (Physics.Raycast(transform.position, -Vector3.up, out hit, 100.0F)) {
	distanceToGround = 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.

function Update() {
	var ray = Camera.main.ScreenPointToRay (Input.mousePosition);

	if (Physics.Raycast (ray, 100)) {
		print ("Hit something");
	}
}

using UnityEngine;
using System.Collections;

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.

function Update() {
	var ray = Camera.main.ScreenPointToRay (Input.mousePosition);
	var hit : RaycastHit;
	if (Physics.Raycast (ray, hit, 100)) {
		Debug.DrawLine (ray.origin, hit.point);
	}
}

using UnityEngine;
using System.Collections;

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);
        }
    }
}