Snow!

[peterguthrie]

I didn't want to continue polluting kimaera's challenge thread with crap about snow so thought I'd start a new thread here.

Just thought I'd share with you all some experiments in making a snow material. First 2 images were my first attempt at snow, firstly without SSS and then with SSS. The one with SSS looks better I think, makes the other one look grey and boring.

The third image was a slight advancement in the material in that I added some bump (3dsmax speckle map) to try and make it sparkle a bit. I also changed the particles to get more and smaller blobs - trying to make it look more like snow and less like shaving foam!. The great thing about using berconmetaballs is that you can experiment to your hearts content without having to wait hours for max to mesh the particles.

link to plugin (you need to be registered on the vray forum though - its a plugin for vray) http://www.chaosgroup.com/forums/vbu...nMetaball-1-10

[peterguthrie]

The settings for the snow material are something like:

diffuse: 244,244,244
reflect: 180,180,180 Fresnel:Y Fresnel IOR: 2.0
reflect glossiness: speckle map, size 25 (I work in mm) dark color rgb54, light color rgb255
refract: rgb75 IOR 1.6 glossiness 0.2 fog color: 89,225,250 fog multiplier: 0.2 fog bias: -0.75
translucency: hybrid back side color: white thickness: 1000 fwd/bck coeff: 0.5 light multiplier: 5.0
bump: 30, speckle map size: 25 black/white

I read somewhere once that its important not to have full 255 for any of the rgb values in the fog color, otherwise the SSS effect won't work.

If anyone has any tips or improvements feel free to add them. I use max 2009 and can share a .mat if its easier. (personally I prefer to recreate materials myself step at a time)

[soulofsound]

Nice one, Peter.

I'd call this icy snow? Maybe fresh snow needs more small holes, like maybe a very fine noise displacement map?

Just a thought.

[peterguthrie]

same render without dof. Its not really doing it for me yet though!

[soulofsound]

Smaller bumps maybe with more noise variation? I'm just guessing here. I'll try to do some snow myself.

I'm also looking at this tutorial
Evermotion Three seasons and night

[artmak]

Hi Peter, great snow experiments and thanks for the plugin link, this should be "snow central" thread here, so people can post their experiments as well!

[peterguthrie]

thats what I'm hoping artmak ;-)

you're right soulofsound, the bump isnt right yet, need to take a look at the example Dave Buckley posted (http://jeffpatton.cgsociety.org/blog.../2007/2/007/2/) by Jeff Patton and see how he did the bump. I think the evermotion link you posted used a bitmap, I'd kind of like to figure out a way of doing it using some kind of procedural map first before I resort to that.

[BBB3]

Great stuff. The latest image is great already.

You might want to check this tutorial by tiagodmed. There's a lot of stuff there, but that includes extremely good snow and ice materials. It's for MR, though, so I don't know how it would translate to Vray. Also, it's over-the-top complex.

[peterguthrie]

thats a really interesting link Bertrand, thanks. Looks like lots of good tips I can take from it, will post the results when I get another chance to play!

[peterguthrie]

Interesting 48euro script: SnowFlow v1.2 - zwischendrin.com (en) - HDRI panoramas, HD textures, stock images, SFX and more

[annkos]

Great snow tests!!! There is another (old)script here but i dont know how good it is.

Nik Clark's Scripts

[peterguthrie]

thanks, didn't know about that one either, will try it before spending money on the other ;-)