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Realistic Snow
Realistic Snow
sdb1987, added 2005-09-13 12:07:12 UTC 96,520 views  Rating:
(3 ratings)
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1. Create a NURBS surface and deform it a bit to get a nice-looking bumpy terrain.
Create a camera




2. Open the Hypershader. Create a Blinn node and edit it as shown below:



I highlighted in red the attributes that need to be edited.
Don't forget the slight blueish Ambience, because snow is always a bit blue when in sunlight.

Also add a light bump (on the example, I use the Turbulence texture, available in the highend3d.com library.
Rename the blinn1 as snowBlinn.

3. Next, create a 2D Fractal texture and edit it as follows:



This texture (fractal1) will simulate the ice crystals that glitter when lit. I use the 2D Fractal node cause it has a Time attribute that allows to phase it. You must also check the Animated box. The phase depends on the value of the Time attribute. This attribute will be later linked to the camera's position using an expression. Also check the Invert box.


4. Remap the fractal1 node (click the Insert button in the Color Remap field), and edit the Ramp as shown:



This is to have stronger glitters (the fractal alone is too soft, because of its high Threshold).


5. Connect the outAlpha of the RemapRamp1 to the SpecularRollOut of the snowBlinn.
You could also link the outColor to the SpecularColor, the result is the same.

This is what you should see in the Hypershade:



Render the scene:



6. This is close to what we want to get, but if we move the camera, the glitters stay at the same place. Now we're creating a very simple expression that links the camera's translation attributes to the fractal1's Time value. If you kept the same names given to the objects along this tutorial, you can copy-paste the following expression. Otherwise you'll have to edit it yourself to make it fit your scene.


fractal1.time = (camera1.tx + camera1.ty + camera1.tz) / 3;


Here I map the average of the camera's 3 XYZ translations to the Time attribute. But feel free to use another value than 3, to control the glittering speed.

7. That's it! If you animate the camera, the snow will glitter as the view changes. As a final touch, you can also put a special attribute instead of the 3 in the expression, so that you have more control of the glittering speed.

Scene File Neige.zip