Reduce Skid Mark Alpha Gradually

For my car war game, I have generated skid marks as the car takes a turn. It's working properly, now after a few seconds passed, I want to reduce its alpha and remove it from the game. I have used trail renderer to generate skid marks.

• what shader do I require to assign to the material?
• which way I can reduce its alpha?

At present, I have used this kind of trail renderer material:


Now for reducing alpha gradually, I have this kind of code:

Code (CSharp):

1. private IEnumerator Start()
2. {
3.     Material myMaterial = GetComponent<Renderer>().material;
4.  
5.     while (true)
6.     {
7.         yield return new WaitForSeconds(1f);
8.  
9.         // check whether this skid trail has finished
10.         // (the Wheel script sets the parent to null when the skid finishes)
11.         if (transform.parent.name == "SkidTrailsDetachedParent")
12.         {
13.  
14.             // set the start colour
15.             //Color startCol = GetComponent<Renderer>().material.color;
16.             //Color startCol = myMaterial.GetColor("_EmisColor");
17.             Color startCol = myMaterial.GetColor("_TintColor");
18.  
19.             // wait for the persist time
20.             yield return new WaitForSeconds(persistTime);
21.  
22.             float t = Time.time;
23.  
24.             // fade out the skid mark
25.             while (Time.time < t + fadeDuration)
26.             {
27.                 float i = Mathf.InverseLerp(t, t + fadeDuration, Time.time);
28.                 //myMaterial.color = startCol * new Color(1, 1, 1, 1 - i);
29.                 //myMaterial.SetColor("_EmisColor", startCol * new Color(1f, 1f, 1f, 1f - i));
30.                 myMaterial.SetColor("_TintColor", startCol * new Color(1f, 1f, 1f, 1f - i));
31.                 yield return null;
32.             }
33.  
34.             // the object has faded and is now done so destroy it
35.             Destroy(gameObject);
36.         }
37.     }
38. }

Still, it's not working for me so I expect some help from your side.

 

Most particle shaders use the mesh's vertex color for things like this. If you're already using a trail renderer, you could modify the color gradient values from script to fade it out.

 

do you mean I require to reduce alpha of trail renderer?
Rather than its material....

 

Yes