Inspired by the wonderful "deep" snow created by Olivier Cousinou I tried to work on something similar on my own, attempting to create a detailed snow layer with a little shiny and somewhat icy crust. The result is a bit complicated surface shader node, and now I'll try to explain with my sloppy english the path I followed. I've also attached a clip file with the entire node.
Here's a capture of the shaders complex (don't mind about the lines on top left, I have some strange issue with my video card)
and a very poor schematic view of how they works
First of all here's
Snow_base. It's a simple surface layer with a max slope constraint, intersect underlying activated (with intersection zone and intersection shift values set to 0) and the "terrain normal" option set as slope key, to render the snow correctly.
The first child surface is
Snow_vertical emboss: this is the surface layer that gives vertical displacement. You can change his "thickness" by playing with displacement offset value; I've set it to 0.1
It has the same slope constraint of Snow_base, but a bit higher fuzzy zone: playing with this value permits you to change the shape of snow edges, following this scheme
The second child surface is
Snow_lateral emboss: this is a power fractal shader with displacement set on "lateral only", to give a somewhat "bumpy" appearance to the snow borders.
Then we have another child surface, named
Snow_grainy surface: this is another surface layer with max slope constraint set on a bit lower value than the others, to limit his action on top of the snow. It creates a fuzzy and grainy surface using a power fractal shader as displacement function, with very small values.
Finally here's a default shader named
Snow_shader, used to give some shininess, reflectivity and translucency to the resulting surface.
Here are two test renders
note on the second image some beautiful feature like "dusty" and icy fragments, as you can see sometime in natural snow
Depending on the slope and the type of image you want to achieve you'll have to play very much with fuzzy zone and displacement offset on the
Snow_vertical emboss layer, to define a good shape for the snow edges.
Hope you've understood my explanation
If anyone wants to work on the .tgc file to improve it or to give some hint is very welcome!
Regards,
Lucio
