Physically accurate materials using IOR and fresnel waveform layer

Layer Setup

Add a gradient and waveform>fresnel on top of your material layer. Set the gradient and fresnel "effect" column to "Specular amount"

>Material Group
- +Fresnel (effect: specular amount)
- +Gradient (effect: specular amount)
- Material

Подробнее тут  http://community.thefoundry.co.uk/discussion/topic.aspx?f=36&t=66395