function Update () {
    var hits : RaycastHit[];
    hits = Physics.RaycastAll (transform.position, transform.forward, 100.0);

    // Change the material of all hit colliders
    // to use a transparent Shader
    for (var i = 0;i < hits.Length; i++) {
        var hit : RaycastHit = hits[i];
        var renderer =  hit.collider.renderer;
        if (renderer) {
            renderer.material.shader = Shader.Find("Transparent/Diffuse");
            renderer.material.color.a = 0.3;
        }
    }
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    void Update() {
        RaycastHit[] hits;
        hits = Physics.RaycastAll(transform.position, transform.forward, 100.0F);
        int i = 0;
        while (i < hits.Length) {
            RaycastHit hit = hits[i];
            Renderer renderer = hit.collider.renderer;
            if (renderer) {
                renderer.material.shader = Shader.Find("Transparent/Diffuse");
                renderer.material.color.a = 0.3F;
            }
            i++;
        }
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    def Update():
        hits as (RaycastHit)
        hits = Physics.RaycastAll(transform.position, transform.forward, 100.0F)
        i as int = 0
        while i < hits.Length:
            hit as RaycastHit = hits[i]
            renderer as Renderer = hit.collider.renderer
            if renderer:
                renderer.material.shader = Shader.Find('Transparent/Diffuse')
                renderer.material.color.a = 0.3F
            i++