Shader Properties

Use Bump

Dictates whether the output of the bump channel will be used in the calculation of the falloff.

Render

Front Only

Calculates the falloff for the front of the object and then sets the back of the object to black if it can be seen.

Front Trans

Calculates the falloff for the front of the object and then sets the back of the object to white if it can be seen (good for use in the transparency channel).

Back Only

Calculates the falloff for the back of the object and then sets the front of the object to black if it can be seen.

Back Trans

Calculates the falloff for the back of the object and then sets the front of the object to white if it can be seen.

Front and Back

Calculates the falloff for all surfaces intercepted.

Gradient

This shader calculates the angle (falloff) between surface Normals and the viewing angle and uses this information to attenuate the output.

Physical

This option lets you create a physically calculated Fresnel effect.

IOR [1..+∞]
Preset

Larger IOR values will reflect correspondingly more in frontal regions.

The Index of Refraction is known more from light refraction effects but it in fact represents a measure of the light reflection of a given material (regardless of whether its transparent or not). As you can see in the image above, lesser IOR values cause the material to reflect almost exclusively in regions in which the camera views an object at a very flat angle (in proximity of edges). Larger values result in correspondingly more frontal regions to reflect.

A Selection of predefined material is available in the Preset menu. Several more indices can be found under Refraction.

Invert

Enabling this option will invert the Fresnel effect, i.e., frontal regions will reflect very strongly and less frontal regions will reflect correspondingly less.