How to make object turn transparent then solid again through a time duration?

• http://docs.unity3d.com/Documentation/ScriptReference/Renderer.html

• http://docs.unity3d.com/Documentation/ScriptReference/Renderer-material.html

• http://docs.unity3d.com/Documentation/ScriptReference/Material.html

• http://docs.unity3d.com/Documentation/ScriptReference/Material-color.html

• http://docs.unity3d.com/Documentation/ScriptReference/Color.html

• http://docs.unity3d.com/Documentation/ScriptReference/Color-a.html

from those Unity Script Reference links it can be derived : to modify the alpha channel of a color, of a material, that is associated with the renderer, use

 renderer.material.color.a = newAlpha;

Note that the alpha channel value is between 0 and 1 (not 0 and 255). And all the colour values are the same, between 0 and 1.

To do this over time, you need to implement a timer.

This is from one of my scripts. It has the basic functionality you are asking for. As the health is decreased, the alpha is increased :

 #pragma strict
 
 var health : float = 100.0;
 private var startingHealth : float;
 var healthDecayRate : float = 5.0;
 
 function Start() 
 {
     startingHealth = health;
     renderer.material.color.a = 0.0;
 }
 
 function Update() 
 {
     DecreaseHealth();
 }
 
 function DecreaseHealth() 
 {
     var decayModifier : float = startingHealth / healthDecayRate;
     
     health -= decayModifier * Time.deltaTime;
     
     // calculate the alpha
     var newAlpha : float = 1.0 - (health / startingHealth);
     
     renderer.material.color.a = newAlpha;
     
     if ( health <= 0.0 )
     {
         Debug.Log( "Player is OUT OF HEALTH" );
     }
 }

if you want the alpha to decrease as the health drops, change this line :

 // calculate the alpha
 var newAlpha : float = health / startingHealth;