---
title: "Fuzz Parameters"
canonical: "https://rmanwiki-26.pixar.com/space/REN26/19661449/Fuzz%20Parameters"
format: markdown
---
> ⚠️ In the parameters below, some of them can be overridden by a [PxrLayer](https://renderman.atlassian.net/wiki/spaces/REN26/pages/19661459) when connected to the **Input Material **or through a [PxrLayerMixer](https://renderman.atlassian.net/wiki/spaces/REN26/pages/19661465). [PxrLayerSurface](https://renderman.atlassian.net/wiki/spaces/REN26/pages/19661463) is designed to better illustrate which parameters are not able to be overridden in a layer by including only parameters that are global. We recommend this material when you know you will be layering. The results of these settings are unchanged.
> ⚠️ 
> ⚠️ - **Bold Face** parameters are layerable, able to be overridden per layer.
> ⚠️ - *Italicized* parameters are not able to be layered or overridden. These are globally obeyed for all layers. For example: Choosing GGX as a specular model will mean all layers will be GGX for that parameter.

> Macro (anchor)



### Fuzz Parameters

This parameter introduces a bit of retroreflection and helps simulate fabrics, fuzz, and fine powder.

**Gain**

Fuzz weight. Higher numbers increase this effect. Below the **Cone Angle** is set to 16.

  


  


**Color**

Fuzz color. This simulates a soft velvety-like effect. This is applied "on top" of the previous Specular lobes and may resemble dirt or fine dust. Below the **Cone Angle** is set to 16.

  


  


**Cone Angle**

Fuzz roughness (corresponding to Marschner R cone angle). Note that we use something from Marschner's hair model here. This helps to simulate a similar response to hair/fur. Higher numbers increase the effect at facing angles. Below are values 8, 16, and 20.

  


  


**Bump**

Normal to use for the fuzz illumination. If this is not set, it will use the global bump normal specified in the Properties near the bottom of this page.

  


  


*Double Sided*

If on, illuminate on both sides of the surface for this fuzz lobe, that is, this will illuminate the surface whose normal is pointing away from the camera as well.  
  


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![image](media://071c2ff2-d64f-4e5a-be53-ba90a941eb80)

**RenderMan Fundamentals**  
  


> Macro (iframe)

  


  


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