var hitPoints : float = 10.0;
function ApplyHitPoints (explosionPos : Vector3, radius : float) {
    // The distance from the explosion position to the surface of the rigidbody
    var closestPoint : Vector3 = rigidbody.ClosestPointOnBounds(explosionPos);
    var distance : float = Vector3.Distance(closestPoint, explosionPos);

    // The hit points we apply fall decrease with distance from the hit point
    var damage : float  = 1.0 - Mathf.Clamp01(distance / radius);
    
    // This is the final hitpoints we want to apply. 10 at maximum.
    damage *= 10;
    
    // Apply the damage
    hitPoints -= damage;
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    public float hitPoints = 10.0F;
    void ApplyHitPoints(Vector3 explosionPos, float radius) {
        Vector3 closestPoint = rigidbody.ClosestPointOnBounds(explosionPos);
        float distance = Vector3.Distance(closestPoint, explosionPos);
        float damage = 1.0F - Mathf.Clamp01(distance / radius);
        damage *= 10;
        hitPoints -= damage;
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    public hitPoints as single = 10.0F

    def ApplyHitPoints(explosionPos as Vector3, radius as single):
        closestPoint as Vector3 = rigidbody.ClosestPointOnBounds(explosionPos)
        distance as single = Vector3.Distance(closestPoint, explosionPos)
        damage as single = (1.0F - Mathf.Clamp01((distance / radius)))
        damage *= 10
        hitPoints -= damage