public static Collider[] OverlapSphere (Vector3 position, float radius, int layerMask= AllLayers, QueryTriggerInteraction queryTriggerInteraction= QueryTriggerInteraction.UseGlobal);


position Center of the sphere.
radius Radius of the sphere.
layerMask A Layer mask that is used to selectively ignore colliders when casting a ray.
queryTriggerInteraction Specifies whether this query should hit Triggers.


Returns an array with all colliders touching or inside the sphere.

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour { void ExplosionDamage(Vector3 center, float radius) { Collider[] hitColliders = Physics.OverlapSphere(center, radius); int i = 0; while (i < hitColliders.Length) { hitColliders[i].SendMessage("AddDamage"); i++; } } }