Snow Layer Shader Help

[jsahn]

hi everyone,
i'm texturing a winter forest scene covered with snow, and i need help making a snow shader. i want to use a layer shader, so when i just apply it to different objects, it'll show the snow on top of them. i'm looking for ways to avoid texturing the snow on every single object in my scene including trees, and the key feature would be to have the snow lying on objects. would this be possible?

i found this brief tutorial on how to make it, but it just give you an idea, not very thorough.
http://www.alias.com/eng/support/studiotoo...dTextures3.html

any ideas will help.

thanks!

h.