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Flashfire
07-15-2003, 04:48 PM
I'm more than sure I could figure this out almost immediately if I were to do a little R&D on my own, but I feel incredibly sure this has done before, so I put it to the group - does anyone know how to add those particulate shimmers (specular) you'd see on an unblemished field of snow?

Preferably something this isn't static, which I assume would lend itself towards the incidence angle gradient....

Thanks in advance and cheers!

lightwolf
07-15-2003, 05:04 PM
Hi Flashfire,
for snow I add a "microbump" map to the snow (very tiny, but strong fractal noise). Mind you this will look different depending on the antialiasing...
Also, adding a blue ambient (or better, a small rig of "atmoshpere" lights) adds to the look.
Cheers,
Mike

Arte
07-15-2003, 09:43 PM
I like Lightwolf's idea but would add an incidence gradient as an alpha to control the effect.

You could also add a similar , very light diffusion map, or if you really want to make things funky, play with the surface thickness gradient on luminosity.

Then again going for a displacement map would be even better but might take a few years to render:)

BTW this can also be done in post.

X

Mattoo
07-16-2003, 12:11 AM
I'd probably try the ideas above first. But if you wanted a perhaps slighlty more exagerated, sparse, sparkly look you might try this more bonkers idea:

How about sprinkle a whole ton of particles onto the snow shape (lots of plugs to do this available).
Then, set the surface of these particles to luminous white.
Then apply a highly contrasted fractal noise to the transparency channel and apply the position coordinates to the camera.

That way, when the camera moves you'd get the sparkly effect. I'm not sure a standard fresnel effect on snow is quite so obvious as one would think, remember it's a very grainy surface so it would be less apparent.
Ofcourse if you find that's lacking you could add that to the snow texture anyway as suggested above.

Remember also that snow is a very rough surface so you might want to find an Oren-Nayer shader somewhere and have a play with that, should take the plasticy feel off of it.

HowardM
07-16-2003, 12:18 AM
easier yet, you could do the same thing with a fine bump texture in the reflection channel...should create sparkly bumps as the camera turns depending on your reflection map.....
also, i bet the Corona Image filter could be used somehow to do some cool little twinkles/sheens...

duke
07-16-2003, 02:39 AM
Or you could try using the crust procedural in the specularity channel. I did this a while back and never finished it so it naturally doesn't look finished :hmm:

http://home.pacific.net.au/~gjrolfe/empires/GlycenPipeline_test_H.jpg

Flashfire
07-16-2003, 05:31 AM
Thanks to you all! :) There's a lot of great ideas for me to play with... I actually figured it'd end up being something very simple... but then, you never know until you ask or try...

Thanks again!

HowardM
07-16-2003, 06:22 AM
very nice duke!
are those displaced hills, that look kinda like sand dunes, with the tight tops? looks like the smoky texture for that or a bump, but really looks good!
:)

duke
07-16-2003, 06:38 AM
Thanks :beer: I think I used turbnoise for the snow displacement, then I used it in the bump channel to accentuate the shape and get a sharper look.

The main displacement of the mountains and so on was done with WorldMachine (http://students.washington.edu/sschmitt/world) , a cool, free, terrain heightmap making program

Flashfire
07-16-2003, 08:03 AM
Originally posted by duke
Thanks :beer: I think I used turbnoise for the snow displacement, then I used it in the bump channel to accentuate the shape and get a sharper look.

The main displacement of the mountains and so on was done with WorldMachine (http://students.washington.edu/sschmitt/world) , a cool, free, terrain heightmap making program Thanks for that link! Thats a nice little program! Exactly what Im looking for...

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