Just do it like Jean said. The Unity script reference on RaycastAll gives you an example for exact your case except it does not revert the transparency. A list would be a solution, but it gets tricky to determine what renderers have to be reverted, which ones should stay transparent and which ones have to set transparent.

I would write a little script that you can attach dynamically to those renderes which should be transparent. In that script you can implement some kind of falloff and when it'sno longer needed it removes itself.

C#:

Here's an example script that gets dynamically attached to the renderer and the script that do the raycast.

using UnityEngine;
using System.Collections;

public class AutoTransparent : MonoBehaviour
{
    private Shader m_OldShader = null;
    private Color m_OldColor = Color.black;
    private float m_Transparency = 0.3f;
    private const float m_TargetTransparancy = 0.3f;
    private const float m_FallOff = 0.1f; // returns to 100% in 0.1 sec

    public void BeTransparent()
    {
        // reset the transparency;
        m_Transparency = m_TargetTransparancy;
        if (m_OldShader == null)
        {
            // Save the current shader
            m_OldShader = renderer.material.shader;
            m_OldColor  = renderer.material.color;
            renderer.material.shader = Shader.Find("Transparent/Diffuse");
        }
    }
    void Update()
    {
        if (m_Transparency < 1.0f)
        {
            Color C = renderer.material.color;
            C.a = m_Transparency;
            renderer.material.color = C;
        }
        else
        {
            // Reset the shader
            renderer.material.shader = m_OldShader;
            renderer.material.color = m_OldColor;
            // And remove this script
            Destroy(this);
        }
        m_Transparency += ((1.0f-m_TargetTransparancy)*Time.deltaTime) / m_FallOff;
    }
}

//And here the script for the camera to cast the ray / capsule ;

using UnityEngine;
using System.Collections;

public class ClearSight : MonoBehaviour
{
    public float DistanceToPlayer = 5.0f;
    void Update()
    {
        RaycastHit[] hits;
        // you can also use CapsuleCastAll()
        // TODO: setup your layermask it improve performance and filter your hits.
        hits = Physics.RaycastAll(transform.position, transform.forward, DistanceToPlayer);
        foreach(RaycastHit hit in hits)
        {
            Renderer R = hit.collider.renderer;
            if (R == null)
                continue; // no renderer attached? go to next hit
            // TODO: maybe implement here a check for GOs that should not be affected like the player

            AutoTransparent AT = R.GetComponent<AutoTransparent>();
            if (AT == null) // if no script is attached, attach one
            {
                AT = R.gameObject.AddComponent<AutoTransparent>();
            }
            AT.BeTransparent(); // get called every frame to reset the falloff
        }
    }
}

The two script files need to be named like the class names (AutoTransparent and ClearSight).
To ignore your player select your player and change the layer on top of the inspector. Just set the layer to "IgnoreRaycast".

edit I guess your camera script is also on the camera like my ClearSight script.

JS:

var myDistanceZoomed : float;

GetComponent.<ClearSight>().DistanceToPlayer = myDistanceZoomed;

But don't forget: you need the distance in units. If you have the distance already, great, just pass it to my script ;)

Hi SirVictory,

Raycasting would be a start, that is, you raycast from the player position and whatever is hit before the player should be send a message or dealt in some way to become semi transparent. you would need to maintain a list so that you can toggle semi transparent models back when not anymore in front of the player,

Else, you could actually have a box collider starting from the player and pointing at the camera where its size emcopass the player bounds, then anything that collides to that are also in the way.

Otherwise, Physics.CapsuleCast could be also an alternative to building a collider, but very similar in principle, tho the start point would need to be sligtly tweacked and not start right where the player is but slightly closer to the camera to not hit the ground or things to close to the player.

As for the shader, I would replace it with a specific simple one while in front, you might want to have front and backface material for object very close to the camera.

Hope it helps,

Jean

I've implemented the same script posted by Bunny83. Mine is in JavaScript and it changes the transparency gradually.

class AutoTransparent extends MonoBehaviour
{
    private var m_OldShader : Shader = null;
    private var m_OldColor : Color;
    private var m_Transparency : float = 0.3;

    private var m_TargetTransparancy : float = 0.3;
    private var m_FallOff : float = 0.5; // returns to 100% in 0.5 sec

    private var shouldBeTransparent : boolean = true;

    function BeTransparent()
    {
        shouldBeTransparent = true;
    }

    function Start()
    {
        if (renderer.material)
        {   
            // Save the current shader
            m_OldShader = renderer.material.shader;
            renderer.material.shader = Shader.Find("Transparent/Diffuse");

            if (renderer.material.HasProperty("_Color") )
            {
                m_OldColor  = renderer.material.color;
                m_Transparency = m_OldColor.a;
            } else
            {
                m_OldColor = Color.white;
                m_Transparency = 1.0;
            }
        } else
        {
            m_Transparency = 1.0;
        }
    }

    function OnDestroy()
    {
        if (!m_OldShader) return;
        // Reset the shader
        renderer.material.shader = m_OldShader;
        renderer.material.color = m_OldColor;
    }

    function Update()
    {
        //Shoud AutoTransparent component be removed?
        if (!shouldBeTransparent && m_Transparency >= 1.0)
        {
            Destroy(this);
        }

        //Are we fading in our out?
        if (shouldBeTransparent)
        {
            //Fading out
            if (m_Transparency > m_TargetTransparancy)
                m_Transparency -= ( (1.0 - m_TargetTransparancy) * Time.deltaTime) / m_FallOff;
        } else
        {
            //Fading in
            m_Transparency += ( (1.0 - m_TargetTransparancy) * Time.deltaTime) / m_FallOff;
        }

        renderer.material.color.a = m_Transparency;

        //The object will start to become visible again if BeTransparent() is not called
        shouldBeTransparent = false;
    }
}

Here's how you can use it:

var currentRenderer = hit.transform.gameObject.renderer;

//Make transparent
if (currentRenderer)
{
    var autoTransparent : AutoTransparent = currentRenderer.GetComponent("AutoTransparent");

    if (autoTransparent == null)
    {
        currentRenderer.gameObject.AddComponent(AutoTransparent);   
    }

    currentRenderer.SendMessage("BeTransparent");                       
}

Hope somebody finds this useful.

Silly question.
Just how do you assign the scripts? I get errors for hit and stuff. Does one goto the main camera and the other the main object? Player Main Camera Capsule