Just in time for those CG snowball fights, here's some info on a snow material that I've created that implements SSS & glitter. No doubt, It's a bit clunky in it's current state. Perhaps one day I'll have time to learn more about shader writing in mental ray and I'll be able to create my own phenomenon for things like this.

Example image (click to enlarge)


Here's a quick animation of the material:
http://jeffpatton.net/Temp/Mray_snow_JP.mov (right click, save as)

The SSS material uses the hidden lightmap option in order to work with the composite map (or blend, or shellac maps, etc). Therefore, you'll need to edit your subsurface.mi file and disable the "hidden" tags in the lightmap section of the .mi file.

It's best to NOT actually delete the hidden tags, but instead, just put a "#" (without the quotes) in front of the hidden lines. This will disable them by turning them into a remark instead of action. This process is a non-destructive method (instead of deleting the line). So, if something goes wrong, you can simply go back and remove the "#" that you added to restore your .mi file to it's original state.

With that being said, I'd still recommend that you make a backup copy of your .mi files before doing ANY editing.

Here's the Max9 file wth the snowball material:
http://jeffpatton.net/Temp/MR_snow.zip

NOTE:
Can this setup work in Max8? The material uses the carpaint shader for the glitter effect. Now, as some of you already know, the carpaint shader can work in Max8, but there's another problem: SSS lightmaps. This material uses the lightmap option of the SSS fast skin shader and from what I hear, that doesn't work as expected in Max8. Therefore, I'd have to say "no", I don't feel this particular material would work properly in Max8.

"demoniorojo" mentioned the T2S_Illumination shader in the 3dsmax mental ray shader thread:
http://forums.cgsociety.org/showthr...442#post4212442

It's a rather well thought out shader with items like Lafortune highlights & surface coatings. You can find the shader at the tek2shoot.com website here:
http://www.tek2shoot.com/knowledge-...mination-9.html

The shader was originally built for XSI, but Jan SandStröm (aka Pixero) was kind enough to create a Maya version of the shader that in turn can be used in 3dsmax9 (I'm not sure about Max8). To try this shader out yoruself, you'll need to download the Maya port of the shader, which is located at the bottom of the page I linked to above.

Then as usual, place the T2S_illumination.dll file in your shaders folder: (3dsmax9/mentalray/shaders_autoload/shaders)

Then download this modified T2S_illumination.mi file:
http://jeffpatton.net/Blog-images/T2S_Illumination.zip
(3dsmax GUI control created by JAF)

And finally, place the .mi file in your include folder:
(3dsmax9/mentalray/shaders_autoload/include)

Example image (click to enlarge)