====== Schlick's Approximation ======
{{ :dbw:schlicks_render.png?300 |}}

This node is a simple replacement for the fresnel function and allows for the manual design of energy conserving materials - especially of metals.

===== Controls ====
{{ :dbw:tools:schlicks_gui.png?nolink|}}
  * **Facing Reflectivity** This is the reflectivity of the surface when facing the ray/camera
  * **Grazing Reflectivity** The reflectivity at a grazing angle - when the surface normal is at 90° to the ray/camera
  * **Exponent** This controls the curve of the approximated frensel effect. The higher the value the more pronounced the effect.
  * **Strength** The strength can decrease the overall effect
  * **No Preprocess Reflectivity** Sets the reflectiviy to 0 while LightWave renders a pre-pass. This can speed up interpolated radiosity renders.
  * **No Radiosity Reflectivity** Sets the reflectiviy to 0 if the surface is sampled by a ray used to compute radiosity. This can speed up radiosity renders.

===== Inputs =====
{{:tools:schlicks_node.png?nolink |}}
The inputs correspond to the GUI controls.

**Function** is an alternative way to define the fresnel effect, using one the function nodes available in the node editor to determine the relationship between the viewing angle and the amount of reflectivity.

===== Outputs =====
{{  :dbw:tools:schlicks_nodeeditor.png?300|}}
  * **Reflectivity** This is the computed reflectivity value and is usually connected to the reflection and/or specular input on a material node.
  * **Inverse** This computes the inverse of the reflectivity value and is usually connected to the diffuse input of a material node for energy conservation.

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===== Supporting Material=====
[[http://experts.adobeconnect.com/p80xqn8k073/|{{  :dbw:tools:comb1a-web.jpg?nolink|}}]]
[[http://www.andrewcomb.com/|Andrew Comb]] use Schlick's Approximation alongside other free db&w Tools in his [[http://experts.adobeconnect.com/p80xqn8k073/|Advanced Shading Tutorial]] presented at the [[http://www.lightwaveusers.com/|San Diego LightWave Users Group]].