How to create RainDrops_LQ0/1/2 asset files from Angry Bots

I found the RainDrops_LQ0/1/2 asset files in Angry Bots project.it's made by unity not 3DMax.But i don't kown how to create that file.
In Rain shader file,there is a line below:
v.vertex.yzx += v.texcoord1.xyy
This line is a way to Zoom Out the meshfilter.But i can't figure how to make the uv2(texcoord1) data?
Anyone konw the way?

 

Easier to get this.
https://www.assetstore.unity3d.com/en/#!/content/19248

 

thanks for share.it's easy to make Rain & Snow effect.
By the way,I just want to konw how to create asset file ,and how to use the UV2 data.

 

http://docs.unity3d.com/Manual/Prefabs.html

 

not the right answer