Making Snow in Maya 2010by Niklas Brandin Web: labs.ravenproduktion.se


15. Scroll down to the bump-slot. Don’t assign anything yet. Open the hypergraph, and create a new mi_bump_flakes node. You´ll find it under Create mental ray nodes > textures.

Now middlemousedrag the new node in the hypershade to your last created mia_material and choose “other”. Select “out value” on the left, and “standard bump” on the right, and press close. Set the strength in the flake parameters to 4.



Since the result of the render is dependent of the scene scale, you have to tweak some of the values to make it look the way you want. This include the light setup, the values of your solid fracture, the SSS-values and the bump value of the flakes. This is a process of trial and error, until you get a satisfying result.



The example scene provided with this tutorial uses the same basic workflow but has a few tweaks to it to show how one could take this shader a few steps further.

It has some minor tweaks to the quality settings but not really anything that changes the overall look of the scene. The most major addition is the use of indirect light using final gathering. Using final gather and physical sky gives us an easy way to add in that blueish tint in a natural way. Since we only want the ambient contribution of the sky and not the direct sunlight the sun shader is disabled and used only to control the sky.

Also the "include indirect light" option on the lightmap shader has been turned on to allow the sky to scatter within the snow. And lastly the lightmap shader has been added to the shading groups of occluding objects to ensure that we don't run into any strange light artifacts.

Note.- This technique would probably work just as well with the use of ambient occlusion /bent normals instead of final gather in situations where complex light and movement causes final gather to flicker or misbehave, but that's really a topic for another tutorial :). Example Scene - Download

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