Rigidbody.SweepTest
SweepTest(direction: Vector3, hitInfo: RaycastHit, distance: float = Mathf.Infinity): bool;
bool SweepTest(Vector3 direction, RaycastHit hitInfo, float distance = Mathf.Infinity);
def SweepTest(direction as Vector3, hitInfo as RaycastHit, distance as float = Mathf.Infinity) as bool
Parameters

direction The direction into which to sweep the rigidbody.
hitInfo If true is returned, hitInfo will contain more information about where the collider was hit (See Also: RaycastHit).
distance The length of the sweep.
Returns
bool True when the rigidbody sweep intersects any collider, otherwise false.
Description

Tests if a rigidbody would collide with anything, if it was moved through the scene.

This is similar to doing a Physics.Raycast for all points contained in any of a Rigidbody's colliders and returning the closest of all hits (if any) reported. This is useful for AI code, when you need to know if an object would fit somewhere without colliding with anything.

Note that this function only works when a primitive collider type (sphere, cube or capsule) is attached to the rigidbody object - mesh colliders will not work, although they can be detected in the scene by the sweep.

See Also: Physics.SphereCast, Physics.CapsuleCast, Rigidbody.SweepTestAll.
	var hit : RaycastHit;

function Update () { // Cast rigidbody shape 10 meters forward, to see if it is about to hit anything if (rigidbody.SweepTest (transform.forward, hit, 10)) { Debug.Log(hit.distance + "mts distance to obstacle"); } }
using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    public RaycastHit hit;
    void Update() {
        if (rigidbody.SweepTest(transform.forward, out hit, 10))
            Debug.Log(hit.distance + "mts distance to obstacle");
        
    }
}
import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	public hit as RaycastHit

	def Update() as void:
		if rigidbody.SweepTest(transform.forward, , 10):
			Debug.Log((hit.distance + 'mts distance to obstacle'))