How to make a realistic snow material in Cycles?

Question

I have looked at many snow shaders, but haven't yet come up with one that looks good. I have many examples of not so good looking snow that I have tried to make.

I have looked at these materials:
Youtube tutorial
thread on blender artists
about the same material on blendswap
another material on blendswap

All of which have disappointed me in some way.
I'm looking for some way to capture the displacement, both small and large, the bright highlights of glistening snow, and the subtle grain over all.

Here are two reference images I took last winter.
close up of snow snow

You may be looking for something like this, I think a combination with Volumetric shader would be worth trying. — Leon Cheung, Nov 07 '14 at 05:07
Could you add a reference image which shows the kind of effects you want? — gandalf3, Nov 07 '14 at 19:25
While I cannot answer the question directly, I would like to point you to the procedural snow shader contained in this shader pack from BlenderCookie (I think the shader was made by Kent Trammel): http://cgcookiemarkets.com/blender/all-products/cgc-shader-pack-vol-1/ It is one of the better snow materials I have seen. While I am not able to produce the node setup to show you, as I have not purchased the shader pack, the node setups ARE considered "open" (that is, even though they are for sale, their licensing permits their being freely shared after purchase) and so you may be able to find some — , Nov 09 '14 at 01:08
It's incredibly hard to create a material that works at a microscopic scale as well as at macroscopic level. The level of detail requirement is simply very different. I'd focus on producing maybe 2 shaders, one for closeups and one for medium to long shots. — Mike Pan, Nov 10 '14 at 06:12
While it is a citizen tutorial the snow shader forge does a good material and each part is explained so you understand how to adjust it to your needs. — sambler, Nov 10 '14 at 14:18

PGmath · Answer 1 · 2015-07-11T02:16:35.323

Here is what I have come up with:

enter image description here

In a still shot the sparkles look kind of like fireflies, but when you animate the camera they look great!

Here is the node setup:

enter image description here

The base material is the diffuse and glossy mix. It uses a fresnel the opposite as you would normally, grazing angles give more diffuse. I have found that this looks quite good. There is also a slight bit of bump applied to the diffuse which greatly enhances the look. You can adjust the roughness on the glossy shader to change how icy the snow looks, smaller roughness = more icy. Values between .025 and .1 work well, I am using .1 for a fresh snow look.

The second layer is technically not photorealistic since I am adding as opposed to mixing in a gloss, but it looks pretty good. It consists of a glossy shader mixed with no shader (this is so we are adding a fraction of a shader) and then added to the base shader. The glossy has a very small voroni texture plugged into the normal to get the sparkles.

Here is a close up, for this I used an even smaller voroni, size = 30,000:

enter image description here

The purplish/yellowish is from the HDR, I am using Greg Zaal's Golden Gate.

The mesh is just a large bent plane with six subsurf levels and two displacement modifiers using different sized clouds textures.

The separate/combine RGB nodes just filter out the green channel of the voroni so it looks like a normal map :). It's totally unnecessary but you could use it to change the strength if you want.